[sql] Import reference version of SQLite 3.17..

third_party/sqlite/sqlite-src-3170000/src/expr.c

+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains routines used for analyzing expressions and
+** for generating VDBE code that evaluates expressions in SQLite.
+*/
+#include "sqliteInt.h"
+
+/* Forward declarations */
+static void exprCodeBetween(Parse*,Expr*,int,void(*)(Parse*,Expr*,int,int),int);
+static int exprCodeVector(Parse *pParse, Expr *p, int *piToFree);
+
+/*
+** Return the affinity character for a single column of a table.
+*/
+char sqlite3TableColumnAffinity(Table *pTab, int iCol){
+  assert( iCol<pTab->nCol );
+  return iCol>=0 ? pTab->aCol[iCol].affinity : SQLITE_AFF_INTEGER;
+}
+
+/*
+** Return the 'affinity' of the expression pExpr if any.
+**
+** If pExpr is a column, a reference to a column via an 'AS' alias,
+** or a sub-select with a column as the return value, then the 
+** affinity of that column is returned. Otherwise, 0x00 is returned,
+** indicating no affinity for the expression.
+**
+** i.e. the WHERE clause expressions in the following statements all
+** have an affinity:
+**
+** CREATE TABLE t1(a);
+** SELECT * FROM t1 WHERE a;
+** SELECT a AS b FROM t1 WHERE b;
+** SELECT * FROM t1 WHERE (select a from t1);
+*/
+char sqlite3ExprAffinity(Expr *pExpr){
+  int op;
+  pExpr = sqlite3ExprSkipCollate(pExpr);
+  if( pExpr->flags & EP_Generic ) return 0;
+  op = pExpr->op;
+  if( op==TK_SELECT ){
+    assert( pExpr->flags&EP_xIsSelect );
+    return sqlite3ExprAffinity(pExpr->x.pSelect->pEList->a[0].pExpr);
+  }
+  if( op==TK_REGISTER ) op = pExpr->op2;
+#ifndef SQLITE_OMIT_CAST
+  if( op==TK_CAST ){
+    assert( !ExprHasProperty(pExpr, EP_IntValue) );
+    return sqlite3AffinityType(pExpr->u.zToken, 0);
+  }
+#endif
+  if( op==TK_AGG_COLUMN || op==TK_COLUMN ){
+    return sqlite3TableColumnAffinity(pExpr->pTab, pExpr->iColumn);
+  }
+  if( op==TK_SELECT_COLUMN ){
+    assert( pExpr->pLeft->flags&EP_xIsSelect );
+    return sqlite3ExprAffinity(
+        pExpr->pLeft->x.pSelect->pEList->a[pExpr->iColumn].pExpr
+    );
+  }
+  return pExpr->affinity;
+}
+
+/*
+** Set the collating sequence for expression pExpr to be the collating
+** sequence named by pToken.   Return a pointer to a new Expr node that
+** implements the COLLATE operator.
+**
+** If a memory allocation error occurs, that fact is recorded in pParse->db
+** and the pExpr parameter is returned unchanged.
+*/
+Expr *sqlite3ExprAddCollateToken(
+  Parse *pParse,           /* Parsing context */
+  Expr *pExpr,             /* Add the "COLLATE" clause to this expression */
+  const Token *pCollName,  /* Name of collating sequence */
+  int dequote              /* True to dequote pCollName */
+){
+  if( pCollName->n>0 ){
+    Expr *pNew = sqlite3ExprAlloc(pParse->db, TK_COLLATE, pCollName, dequote);
+    if( pNew ){
+      pNew->pLeft = pExpr;
+      pNew->flags |= EP_Collate|EP_Skip;
+      pExpr = pNew;
+    }
+  }
+  return pExpr;
+}
+Expr *sqlite3ExprAddCollateString(Parse *pParse, Expr *pExpr, const char *zC){
+  Token s;
+  assert( zC!=0 );
+  sqlite3TokenInit(&s, (char*)zC);
+  return sqlite3ExprAddCollateToken(pParse, pExpr, &s, 0);
+}
+
+/*
+** Skip over any TK_COLLATE operators and any unlikely()
+** or likelihood() function at the root of an expression.
+*/
+Expr *sqlite3ExprSkipCollate(Expr *pExpr){
+  while( pExpr && ExprHasProperty(pExpr, EP_Skip) ){
+    if( ExprHasProperty(pExpr, EP_Unlikely) ){
+      assert( !ExprHasProperty(pExpr, EP_xIsSelect) );
+      assert( pExpr->x.pList->nExpr>0 );
+      assert( pExpr->op==TK_FUNCTION );
+      pExpr = pExpr->x.pList->a[0].pExpr;
+    }else{
+      assert( pExpr->op==TK_COLLATE );
+      pExpr = pExpr->pLeft;
+    }
+  }   
+  return pExpr;
+}
+
+/*
+** Return the collation sequence for the expression pExpr. If
+** there is no defined collating sequence, return NULL.
+**
+** The collating sequence might be determined by a COLLATE operator
+** or by the presence of a column with a defined collating sequence.
+** COLLATE operators take first precedence.  Left operands take
+** precedence over right operands.
+*/
+CollSeq *sqlite3ExprCollSeq(Parse *pParse, Expr *pExpr){
+  sqlite3 *db = pParse->db;
+  CollSeq *pColl = 0;
+  Expr *p = pExpr;
+  while( p ){
+    int op = p->op;
+    if( p->flags & EP_Generic ) break;
+    if( op==TK_CAST || op==TK_UPLUS ){
+      p = p->pLeft;
+      continue;
+    }
+    if( op==TK_COLLATE || (op==TK_REGISTER && p->op2==TK_COLLATE) ){
+      pColl = sqlite3GetCollSeq(pParse, ENC(db), 0, p->u.zToken);
+      break;
+    }
+    if( (op==TK_AGG_COLUMN || op==TK_COLUMN
+          || op==TK_REGISTER || op==TK_TRIGGER)
+     && p->pTab!=0
+    ){
+      /* op==TK_REGISTER && p->pTab!=0 happens when pExpr was originally
+      ** a TK_COLUMN but was previously evaluated and cached in a register */
+      int j = p->iColumn;
+      if( j>=0 ){
+        const char *zColl = p->pTab->aCol[j].zColl;
+        pColl = sqlite3FindCollSeq(db, ENC(db), zColl, 0);
+      }
+      break;
+    }
+    if( p->flags & EP_Collate ){
+      if( p->pLeft && (p->pLeft->flags & EP_Collate)!=0 ){
+        p = p->pLeft;
+      }else{
+        Expr *pNext  = p->pRight;
+        /* The Expr.x union is never used at the same time as Expr.pRight */
+        assert( p->x.pList==0 || p->pRight==0 );
+        /* p->flags holds EP_Collate and p->pLeft->flags does not.  And
+        ** p->x.pSelect cannot.  So if p->x.pLeft exists, it must hold at
+        ** least one EP_Collate. Thus the following two ALWAYS. */
+        if( p->x.pList!=0 && ALWAYS(!ExprHasProperty(p, EP_xIsSelect)) ){
+          int i;
+          for(i=0; ALWAYS(i<p->x.pList->nExpr); i++){
+            if( ExprHasProperty(p->x.pList->a[i].pExpr, EP_Collate) ){
+              pNext = p->x.pList->a[i].pExpr;
+              break;
+            }
+          }
+        }
+        p = pNext;
+      }
+    }else{
+      break;
+    }
+  }
+  if( sqlite3CheckCollSeq(pParse, pColl) ){ 
+    pColl = 0;
+  }
+  return pColl;
+}
+
+/*
+** pExpr is an operand of a comparison operator.  aff2 is the
+** type affinity of the other operand.  This routine returns the
+** type affinity that should be used for the comparison operator.
+*/
+char sqlite3CompareAffinity(Expr *pExpr, char aff2){
+  char aff1 = sqlite3ExprAffinity(pExpr);
+  if( aff1 && aff2 ){
+    /* Both sides of the comparison are columns. If one has numeric
+    ** affinity, use that. Otherwise use no affinity.
+    */
+    if( sqlite3IsNumericAffinity(aff1) || sqlite3IsNumericAffinity(aff2) ){
+      return SQLITE_AFF_NUMERIC;
+    }else{
+      return SQLITE_AFF_BLOB;
+    }
+  }else if( !aff1 && !aff2 ){
+    /* Neither side of the comparison is a column.  Compare the
+    ** results directly.
+    */
+    return SQLITE_AFF_BLOB;
+  }else{
+    /* One side is a column, the other is not. Use the columns affinity. */
+    assert( aff1==0 || aff2==0 );
+    return (aff1 + aff2);
+  }
+}
+
+/*
+** pExpr is a comparison operator.  Return the type affinity that should
+** be applied to both operands prior to doing the comparison.
+*/
+static char comparisonAffinity(Expr *pExpr){
+  char aff;
+  assert( pExpr->op==TK_EQ || pExpr->op==TK_IN || pExpr->op==TK_LT ||
+          pExpr->op==TK_GT || pExpr->op==TK_GE || pExpr->op==TK_LE ||
+          pExpr->op==TK_NE || pExpr->op==TK_IS || pExpr->op==TK_ISNOT );
+  assert( pExpr->pLeft );
+  aff = sqlite3ExprAffinity(pExpr->pLeft);
+  if( pExpr->pRight ){
+    aff = sqlite3CompareAffinity(pExpr->pRight, aff);
+  }else if( ExprHasProperty(pExpr, EP_xIsSelect) ){
+    aff = sqlite3CompareAffinity(pExpr->x.pSelect->pEList->a[0].pExpr, aff);
+  }else if( aff==0 ){
+    aff = SQLITE_AFF_BLOB;
+  }
+  return aff;
+}
+
+/*
+** pExpr is a comparison expression, eg. '=', '<', IN(...) etc.
+** idx_affinity is the affinity of an indexed column. Return true
+** if the index with affinity idx_affinity may be used to implement
+** the comparison in pExpr.
+*/
+int sqlite3IndexAffinityOk(Expr *pExpr, char idx_affinity){
+  char aff = comparisonAffinity(pExpr);
+  switch( aff ){
+    case SQLITE_AFF_BLOB:
+      return 1;
+    case SQLITE_AFF_TEXT:
+      return idx_affinity==SQLITE_AFF_TEXT;
+    default:
+      return sqlite3IsNumericAffinity(idx_affinity);
+  }
+}
+
+/*
+** Return the P5 value that should be used for a binary comparison
+** opcode (OP_Eq, OP_Ge etc.) used to compare pExpr1 and pExpr2.
+*/
+static u8 binaryCompareP5(Expr *pExpr1, Expr *pExpr2, int jumpIfNull){
+  u8 aff = (char)sqlite3ExprAffinity(pExpr2);
+  aff = (u8)sqlite3CompareAffinity(pExpr1, aff) | (u8)jumpIfNull;
+  return aff;
+}
+
+/*
+** Return a pointer to the collation sequence that should be used by
+** a binary comparison operator comparing pLeft and pRight.
+**
+** If the left hand expression has a collating sequence type, then it is
+** used. Otherwise the collation sequence for the right hand expression
+** is used, or the default (BINARY) if neither expression has a collating
+** type.
+**
+** Argument pRight (but not pLeft) may be a null pointer. In this case,
+** it is not considered.
+*/
+CollSeq *sqlite3BinaryCompareCollSeq(
+  Parse *pParse, 
+  Expr *pLeft, 
+  Expr *pRight
+){
+  CollSeq *pColl;
+  assert( pLeft );
+  if( pLeft->flags & EP_Collate ){
+    pColl = sqlite3ExprCollSeq(pParse, pLeft);
+  }else if( pRight && (pRight->flags & EP_Collate)!=0 ){
+    pColl = sqlite3ExprCollSeq(pParse, pRight);
+  }else{
+    pColl = sqlite3ExprCollSeq(pParse, pLeft);
+    if( !pColl ){
+      pColl = sqlite3ExprCollSeq(pParse, pRight);
+    }
+  }
+  return pColl;
+}
+
+/*
+** Generate code for a comparison operator.
+*/
+static int codeCompare(
+  Parse *pParse,    /* The parsing (and code generating) context */
+  Expr *pLeft,      /* The left operand */
+  Expr *pRight,     /* The right operand */
+  int opcode,       /* The comparison opcode */
+  int in1, int in2, /* Register holding operands */
+  int dest,         /* Jump here if true.  */
+  int jumpIfNull    /* If true, jump if either operand is NULL */
+){
+  int p5;
+  int addr;
+  CollSeq *p4;
+
+  p4 = sqlite3BinaryCompareCollSeq(pParse, pLeft, pRight);
+  p5 = binaryCompareP5(pLeft, pRight, jumpIfNull);
+  addr = sqlite3VdbeAddOp4(pParse->pVdbe, opcode, in2, dest, in1,
+                           (void*)p4, P4_COLLSEQ);
+  sqlite3VdbeChangeP5(pParse->pVdbe, (u8)p5);
+  return addr;
+}
+
+/*
+** Return true if expression pExpr is a vector, or false otherwise.
+**
+** A vector is defined as any expression that results in two or more
+** columns of result.  Every TK_VECTOR node is an vector because the
+** parser will not generate a TK_VECTOR with fewer than two entries.
+** But a TK_SELECT might be either a vector or a scalar. It is only
+** considered a vector if it has two or more result columns.
+*/
+int sqlite3ExprIsVector(Expr *pExpr){
+  return sqlite3ExprVectorSize(pExpr)>1;
+}
+
+/*
+** If the expression passed as the only argument is of type TK_VECTOR 
+** return the number of expressions in the vector. Or, if the expression
+** is a sub-select, return the number of columns in the sub-select. For
+** any other type of expression, return 1.
+*/
+int sqlite3ExprVectorSize(Expr *pExpr){
+  u8 op = pExpr->op;
+  if( op==TK_REGISTER ) op = pExpr->op2;
+  if( op==TK_VECTOR ){
+    return pExpr->x.pList->nExpr;
+  }else if( op==TK_SELECT ){
+    return pExpr->x.pSelect->pEList->nExpr;
+  }else{
+    return 1;
+  }
+}
+
+#ifndef SQLITE_OMIT_SUBQUERY
+/*
+** Return a pointer to a subexpression of pVector that is the i-th
+** column of the vector (numbered starting with 0).  The caller must
+** ensure that i is within range.
+**
+** If pVector is really a scalar (and "scalar" here includes subqueries
+** that return a single column!) then return pVector unmodified.
+**
+** pVector retains ownership of the returned subexpression.
+**
+** If the vector is a (SELECT ...) then the expression returned is
+** just the expression for the i-th term of the result set, and may
+** not be ready for evaluation because the table cursor has not yet
+** been positioned.
+*/
+Expr *sqlite3VectorFieldSubexpr(Expr *pVector, int i){
+  assert( i<sqlite3ExprVectorSize(pVector) );
+  if( sqlite3ExprIsVector(pVector) ){
+    assert( pVector->op2==0 || pVector->op==TK_REGISTER );
+    if( pVector->op==TK_SELECT || pVector->op2==TK_SELECT ){
+      return pVector->x.pSelect->pEList->a[i].pExpr;
+    }else{
+      return pVector->x.pList->a[i].pExpr;
+    }
+  }
+  return pVector;
+}
+#endif /* !defined(SQLITE_OMIT_SUBQUERY) */
+
+#ifndef SQLITE_OMIT_SUBQUERY
+/*
+** Compute and return a new Expr object which when passed to
+** sqlite3ExprCode() will generate all necessary code to compute
+** the iField-th column of the vector expression pVector.
+**
+** It is ok for pVector to be a scalar (as long as iField==0).  
+** In that case, this routine works like sqlite3ExprDup().
+**
+** The caller owns the returned Expr object and is responsible for
+** ensuring that the returned value eventually gets freed.
+**
+** The caller retains ownership of pVector.  If pVector is a TK_SELECT,
+** then the returned object will reference pVector and so pVector must remain
+** valid for the life of the returned object.  If pVector is a TK_VECTOR
+** or a scalar expression, then it can be deleted as soon as this routine
+** returns.
+**
+** A trick to cause a TK_SELECT pVector to be deleted together with
+** the returned Expr object is to attach the pVector to the pRight field
+** of the returned TK_SELECT_COLUMN Expr object.
+*/
+Expr *sqlite3ExprForVectorField(
+  Parse *pParse,       /* Parsing context */
+  Expr *pVector,       /* The vector.  List of expressions or a sub-SELECT */
+  int iField           /* Which column of the vector to return */
+){
+  Expr *pRet;
+  if( pVector->op==TK_SELECT ){
+    assert( pVector->flags & EP_xIsSelect );
+    /* The TK_SELECT_COLUMN Expr node:
+    **
+    ** pLeft:           pVector containing TK_SELECT.  Not deleted.
+    ** pRight:          not used.  But recursively deleted.
+    ** iColumn:         Index of a column in pVector
+    ** iTable:          0 or the number of columns on the LHS of an assignment
+    ** pLeft->iTable:   First in an array of register holding result, or 0
+    **                  if the result is not yet computed.
+    **
+    ** sqlite3ExprDelete() specifically skips the recursive delete of
+    ** pLeft on TK_SELECT_COLUMN nodes.  But pRight is followed, so pVector
+    ** can be attached to pRight to cause this node to take ownership of
+    ** pVector.  Typically there will be multiple TK_SELECT_COLUMN nodes
+    ** with the same pLeft pointer to the pVector, but only one of them
+    ** will own the pVector.
+    */
+    pRet = sqlite3PExpr(pParse, TK_SELECT_COLUMN, 0, 0);
+    if( pRet ){
+      pRet->iColumn = iField;
+      pRet->pLeft = pVector;
+    }
+    assert( pRet==0 || pRet->iTable==0 );
+  }else{
+    if( pVector->op==TK_VECTOR ) pVector = pVector->x.pList->a[iField].pExpr;
+    pRet = sqlite3ExprDup(pParse->db, pVector, 0);
+  }
+  return pRet;
+}
+#endif /* !define(SQLITE_OMIT_SUBQUERY) */
+
+/*
+** If expression pExpr is of type TK_SELECT, generate code to evaluate
+** it. Return the register in which the result is stored (or, if the 
+** sub-select returns more than one column, the first in an array
+** of registers in which the result is stored).
+**
+** If pExpr is not a TK_SELECT expression, return 0.
+*/
+static int exprCodeSubselect(Parse *pParse, Expr *pExpr){
+  int reg = 0;
+#ifndef SQLITE_OMIT_SUBQUERY
+  if( pExpr->op==TK_SELECT ){
+    reg = sqlite3CodeSubselect(pParse, pExpr, 0, 0);
+  }
+#endif
+  return reg;
+}
+
+/*
+** Argument pVector points to a vector expression - either a TK_VECTOR
+** or TK_SELECT that returns more than one column. This function returns
+** the register number of a register that contains the value of
+** element iField of the vector.
+**
+** If pVector is a TK_SELECT expression, then code for it must have 
+** already been generated using the exprCodeSubselect() routine. In this
+** case parameter regSelect should be the first in an array of registers
+** containing the results of the sub-select. 
+**
+** If pVector is of type TK_VECTOR, then code for the requested field
+** is generated. In this case (*pRegFree) may be set to the number of
+** a temporary register to be freed by the caller before returning.
+**
+** Before returning, output parameter (*ppExpr) is set to point to the
+** Expr object corresponding to element iElem of the vector.
+*/
+static int exprVectorRegister(
+  Parse *pParse,                  /* Parse context */
+  Expr *pVector,                  /* Vector to extract element from */
+  int iField,                     /* Field to extract from pVector */
+  int regSelect,                  /* First in array of registers */
+  Expr **ppExpr,                  /* OUT: Expression element */
+  int *pRegFree                   /* OUT: Temp register to free */
+){
+  u8 op = pVector->op;
+  assert( op==TK_VECTOR || op==TK_REGISTER || op==TK_SELECT );
+  if( op==TK_REGISTER ){
+    *ppExpr = sqlite3VectorFieldSubexpr(pVector, iField);
+    return pVector->iTable+iField;
+  }
+  if( op==TK_SELECT ){
+    *ppExpr = pVector->x.pSelect->pEList->a[iField].pExpr;
+     return regSelect+iField;
+  }
+  *ppExpr = pVector->x.pList->a[iField].pExpr;
+  return sqlite3ExprCodeTemp(pParse, *ppExpr, pRegFree);
+}
+
+/*
+** Expression pExpr is a comparison between two vector values. Compute
+** the result of the comparison (1, 0, or NULL) and write that
+** result into register dest.
+**
+** The caller must satisfy the following preconditions:
+**
+**    if pExpr->op==TK_IS:      op==TK_EQ and p5==SQLITE_NULLEQ
+**    if pExpr->op==TK_ISNOT:   op==TK_NE and p5==SQLITE_NULLEQ
+**    otherwise:                op==pExpr->op and p5==0
+*/
+static void codeVectorCompare(
+  Parse *pParse,        /* Code generator context */
+  Expr *pExpr,          /* The comparison operation */
+  int dest,             /* Write results into this register */
+  u8 op,                /* Comparison operator */
+  u8 p5                 /* SQLITE_NULLEQ or zero */
+){
+  Vdbe *v = pParse->pVdbe;
+  Expr *pLeft = pExpr->pLeft;
+  Expr *pRight = pExpr->pRight;
+  int nLeft = sqlite3ExprVectorSize(pLeft);
+  int i;
+  int regLeft = 0;
+  int regRight = 0;
+  u8 opx = op;
+  int addrDone = sqlite3VdbeMakeLabel(v);
+
+  if( nLeft!=sqlite3ExprVectorSize(pRight) ){
+    sqlite3ErrorMsg(pParse, "row value misused");
+    return;
+  }
+  assert( pExpr->op==TK_EQ || pExpr->op==TK_NE 
+       || pExpr->op==TK_IS || pExpr->op==TK_ISNOT 
+       || pExpr->op==TK_LT || pExpr->op==TK_GT 
+       || pExpr->op==TK_LE || pExpr->op==TK_GE 
+  );
+  assert( pExpr->op==op || (pExpr->op==TK_IS && op==TK_EQ)
+            || (pExpr->op==TK_ISNOT && op==TK_NE) );
+  assert( p5==0 || pExpr->op!=op );
+  assert( p5==SQLITE_NULLEQ || pExpr->op==op );
+
+  p5 |= SQLITE_STOREP2;
+  if( opx==TK_LE ) opx = TK_LT;
+  if( opx==TK_GE ) opx = TK_GT;
+
+  regLeft = exprCodeSubselect(pParse, pLeft);
+  regRight = exprCodeSubselect(pParse, pRight);
+
+  for(i=0; 1 /*Loop exits by "break"*/; i++){
+    int regFree1 = 0, regFree2 = 0;
+    Expr *pL, *pR; 
+    int r1, r2;
+    assert( i>=0 && i<nLeft );
+    if( i>0 ) sqlite3ExprCachePush(pParse);
+    r1 = exprVectorRegister(pParse, pLeft, i, regLeft, &pL, &regFree1);
+    r2 = exprVectorRegister(pParse, pRight, i, regRight, &pR, &regFree2);
+    codeCompare(pParse, pL, pR, opx, r1, r2, dest, p5);
+    testcase(op==OP_Lt); VdbeCoverageIf(v,op==OP_Lt);
+    testcase(op==OP_Le); VdbeCoverageIf(v,op==OP_Le);
+    testcase(op==OP_Gt); VdbeCoverageIf(v,op==OP_Gt);
+    testcase(op==OP_Ge); VdbeCoverageIf(v,op==OP_Ge);
+    testcase(op==OP_Eq); VdbeCoverageIf(v,op==OP_Eq);
+    testcase(op==OP_Ne); VdbeCoverageIf(v,op==OP_Ne);
+    sqlite3ReleaseTempReg(pParse, regFree1);
+    sqlite3ReleaseTempReg(pParse, regFree2);
+    if( i>0 ) sqlite3ExprCachePop(pParse);
+    if( i==nLeft-1 ){
+      break;
+    }
+    if( opx==TK_EQ ){
+      sqlite3VdbeAddOp2(v, OP_IfNot, dest, addrDone); VdbeCoverage(v);
+      p5 |= SQLITE_KEEPNULL;
+    }else if( opx==TK_NE ){
+      sqlite3VdbeAddOp2(v, OP_If, dest, addrDone); VdbeCoverage(v);
+      p5 |= SQLITE_KEEPNULL;
+    }else{
+      assert( op==TK_LT || op==TK_GT || op==TK_LE || op==TK_GE );
+      sqlite3VdbeAddOp2(v, OP_ElseNotEq, 0, addrDone);
+      VdbeCoverageIf(v, op==TK_LT);
+      VdbeCoverageIf(v, op==TK_GT);
+      VdbeCoverageIf(v, op==TK_LE);
+      VdbeCoverageIf(v, op==TK_GE);
+      if( i==nLeft-2 ) opx = op;
+    }
+  }
+  sqlite3VdbeResolveLabel(v, addrDone);
+}
+
+#if SQLITE_MAX_EXPR_DEPTH>0
+/*
+** Check that argument nHeight is less than or equal to the maximum
+** expression depth allowed. If it is not, leave an error message in
+** pParse.
+*/
+int sqlite3ExprCheckHeight(Parse *pParse, int nHeight){
+  int rc = SQLITE_OK;
+  int mxHeight = pParse->db->aLimit[SQLITE_LIMIT_EXPR_DEPTH];
+  if( nHeight>mxHeight ){
+    sqlite3ErrorMsg(pParse, 
+       "Expression tree is too large (maximum depth %d)", mxHeight
+    );
+    rc = SQLITE_ERROR;
+  }
+  return rc;
+}
+
+/* The following three functions, heightOfExpr(), heightOfExprList()
+** and heightOfSelect(), are used to determine the maximum height
+** of any expression tree referenced by the structure passed as the
+** first argument.
+**
+** If this maximum height is greater than the current value pointed
+** to by pnHeight, the second parameter, then set *pnHeight to that
+** value.
+*/
+static void heightOfExpr(Expr *p, int *pnHeight){
+  if( p ){
+    if( p->nHeight>*pnHeight ){
+      *pnHeight = p->nHeight;
+    }
+  }
+}
+static void heightOfExprList(ExprList *p, int *pnHeight){
+  if( p ){
+    int i;
+    for(i=0; i<p->nExpr; i++){
+      heightOfExpr(p->a[i].pExpr, pnHeight);
+    }
+  }
+}
+static void heightOfSelect(Select *p, int *pnHeight){
+  if( p ){
+    heightOfExpr(p->pWhere, pnHeight);
+    heightOfExpr(p->pHaving, pnHeight);
+    heightOfExpr(p->pLimit, pnHeight);
+    heightOfExpr(p->pOffset, pnHeight);
+    heightOfExprList(p->pEList, pnHeight);
+    heightOfExprList(p->pGroupBy, pnHeight);
+    heightOfExprList(p->pOrderBy, pnHeight);
+    heightOfSelect(p->pPrior, pnHeight);
+  }
+}
+
+/*
+** Set the Expr.nHeight variable in the structure passed as an 
+** argument. An expression with no children, Expr.pList or 
+** Expr.pSelect member has a height of 1. Any other expression
+** has a height equal to the maximum height of any other 
+** referenced Expr plus one.
+**
+** Also propagate EP_Propagate flags up from Expr.x.pList to Expr.flags,
+** if appropriate.
+*/
+static void exprSetHeight(Expr *p){
+  int nHeight = 0;
+  heightOfExpr(p->pLeft, &nHeight);
+  heightOfExpr(p->pRight, &nHeight);
+  if( ExprHasProperty(p, EP_xIsSelect) ){
+    heightOfSelect(p->x.pSelect, &nHeight);
+  }else if( p->x.pList ){
+    heightOfExprList(p->x.pList, &nHeight);
+    p->flags |= EP_Propagate & sqlite3ExprListFlags(p->x.pList);
+  }
+  p->nHeight = nHeight + 1;
+}
+
+/*
+** Set the Expr.nHeight variable using the exprSetHeight() function. If
+** the height is greater than the maximum allowed expression depth,
+** leave an error in pParse.
+**
+** Also propagate all EP_Propagate flags from the Expr.x.pList into
+** Expr.flags. 
+*/
+void sqlite3ExprSetHeightAndFlags(Parse *pParse, Expr *p){
+  if( pParse->nErr ) return;
+  exprSetHeight(p);
+  sqlite3ExprCheckHeight(pParse, p->nHeight);
+}
+
+/*
+** Return the maximum height of any expression tree referenced
+** by the select statement passed as an argument.
+*/
+int sqlite3SelectExprHeight(Select *p){
+  int nHeight = 0;
+  heightOfSelect(p, &nHeight);
+  return nHeight;
+}
+#else /* ABOVE:  Height enforcement enabled.  BELOW: Height enforcement off */
+/*
+** Propagate all EP_Propagate flags from the Expr.x.pList into
+** Expr.flags. 
+*/
+void sqlite3ExprSetHeightAndFlags(Parse *pParse, Expr *p){
+  if( p && p->x.pList && !ExprHasProperty(p, EP_xIsSelect) ){
+    p->flags |= EP_Propagate & sqlite3ExprListFlags(p->x.pList);
+  }
+}
+#define exprSetHeight(y)
+#endif /* SQLITE_MAX_EXPR_DEPTH>0 */
+
+/*
+** This routine is the core allocator for Expr nodes.
+**
+** Construct a new expression node and return a pointer to it.  Memory
+** for this node and for the pToken argument is a single allocation
+** obtained from sqlite3DbMalloc().  The calling function
+** is responsible for making sure the node eventually gets freed.
+**
+** If dequote is true, then the token (if it exists) is dequoted.
+** If dequote is false, no dequoting is performed.  The deQuote
+** parameter is ignored if pToken is NULL or if the token does not
+** appear to be quoted.  If the quotes were of the form "..." (double-quotes)
+** then the EP_DblQuoted flag is set on the expression node.
+**
+** Special case:  If op==TK_INTEGER and pToken points to a string that
+** can be translated into a 32-bit integer, then the token is not
+** stored in u.zToken.  Instead, the integer values is written
+** into u.iValue and the EP_IntValue flag is set.  No extra storage
+** is allocated to hold the integer text and the dequote flag is ignored.
+*/
+Expr *sqlite3ExprAlloc(
+  sqlite3 *db,            /* Handle for sqlite3DbMallocRawNN() */
+  int op,                 /* Expression opcode */
+  const Token *pToken,    /* Token argument.  Might be NULL */
+  int dequote             /* True to dequote */
+){
+  Expr *pNew;
+  int nExtra = 0;
+  int iValue = 0;
+
+  assert( db!=0 );
+  if( pToken ){
+    if( op!=TK_INTEGER || pToken->z==0
+          || sqlite3GetInt32(pToken->z, &iValue)==0 ){
+      nExtra = pToken->n+1;
+      assert( iValue>=0 );
+    }
+  }
+  pNew = sqlite3DbMallocRawNN(db, sizeof(Expr)+nExtra);
+  if( pNew ){
+    memset(pNew, 0, sizeof(Expr));
+    pNew->op = (u8)op;
+    pNew->iAgg = -1;
+    if( pToken ){
+      if( nExtra==0 ){
+        pNew->flags |= EP_IntValue;
+        pNew->u.iValue = iValue;
+      }else{
+        pNew->u.zToken = (char*)&pNew[1];
+        assert( pToken->z!=0 || pToken->n==0 );
+        if( pToken->n ) memcpy(pNew->u.zToken, pToken->z, pToken->n);
+        pNew->u.zToken[pToken->n] = 0;
+        if( dequote && sqlite3Isquote(pNew->u.zToken[0]) ){
+          if( pNew->u.zToken[0]=='"' ) pNew->flags |= EP_DblQuoted;
+          sqlite3Dequote(pNew->u.zToken);
+        }
+      }
+    }
+#if SQLITE_MAX_EXPR_DEPTH>0
+    pNew->nHeight = 1;
+#endif  
+  }
+  return pNew;
+}
+
+/*
+** Allocate a new expression node from a zero-terminated token that has
+** already been dequoted.
+*/
+Expr *sqlite3Expr(
+  sqlite3 *db,            /* Handle for sqlite3DbMallocZero() (may be null) */
+  int op,                 /* Expression opcode */
+  const char *zToken      /* Token argument.  Might be NULL */
+){
+  Token x;
+  x.z = zToken;
+  x.n = zToken ? sqlite3Strlen30(zToken) : 0;
+  return sqlite3ExprAlloc(db, op, &x, 0);
+}
+
+/*
+** Attach subtrees pLeft and pRight to the Expr node pRoot.
+**
+** If pRoot==NULL that means that a memory allocation error has occurred.
+** In that case, delete the subtrees pLeft and pRight.
+*/
+void sqlite3ExprAttachSubtrees(
+  sqlite3 *db,
+  Expr *pRoot,
+  Expr *pLeft,
+  Expr *pRight
+){
+  if( pRoot==0 ){
+    assert( db->mallocFailed );
+    sqlite3ExprDelete(db, pLeft);
+    sqlite3ExprDelete(db, pRight);
+  }else{
+    if( pRight ){
+      pRoot->pRight = pRight;
+      pRoot->flags |= EP_Propagate & pRight->flags;
+    }
+    if( pLeft ){
+      pRoot->pLeft = pLeft;
+      pRoot->flags |= EP_Propagate & pLeft->flags;
+    }
+    exprSetHeight(pRoot);
+  }
+}
+
+/*
+** Allocate an Expr node which joins as many as two subtrees.
+**
+** One or both of the subtrees can be NULL.  Return a pointer to the new
+** Expr node.  Or, if an OOM error occurs, set pParse->db->mallocFailed,
+** free the subtrees and return NULL.
+*/
+Expr *sqlite3PExpr(
+  Parse *pParse,          /* Parsing context */
+  int op,                 /* Expression opcode */
+  Expr *pLeft,            /* Left operand */
+  Expr *pRight            /* Right operand */
+){
+  Expr *p;
+  if( op==TK_AND && pParse->nErr==0 ){
+    /* Take advantage of short-circuit false optimization for AND */
+    p = sqlite3ExprAnd(pParse->db, pLeft, pRight);
+  }else{
+    p = sqlite3DbMallocRawNN(pParse->db, sizeof(Expr));
+    if( p ){
+      memset(p, 0, sizeof(Expr));
+      p->op = op & TKFLG_MASK;
+      p->iAgg = -1;
+    }
+    sqlite3ExprAttachSubtrees(pParse->db, p, pLeft, pRight);
+  }
+  if( p ) {
+    sqlite3ExprCheckHeight(pParse, p->nHeight);
+  }
+  return p;
+}
+
+/*
+** Add pSelect to the Expr.x.pSelect field.  Or, if pExpr is NULL (due
+** do a memory allocation failure) then delete the pSelect object.
+*/
+void sqlite3PExprAddSelect(Parse *pParse, Expr *pExpr, Select *pSelect){
+  if( pExpr ){
+    pExpr->x.pSelect = pSelect;
+    ExprSetProperty(pExpr, EP_xIsSelect|EP_Subquery);
+    sqlite3ExprSetHeightAndFlags(pParse, pExpr);
+  }else{
+    assert( pParse->db->mallocFailed );
+    sqlite3SelectDelete(pParse->db, pSelect);
+  }
+}
+
+
+/*
+** If the expression is always either TRUE or FALSE (respectively),
+** then return 1.  If one cannot determine the truth value of the
+** expression at compile-time return 0.
+**
+** This is an optimization.  If is OK to return 0 here even if
+** the expression really is always false or false (a false negative).
+** But it is a bug to return 1 if the expression might have different
+** boolean values in different circumstances (a false positive.)
+**
+** Note that if the expression is part of conditional for a
+** LEFT JOIN, then we cannot determine at compile-time whether or not
+** is it true or false, so always return 0.
+*/
+static int exprAlwaysTrue(Expr *p){
+  int v = 0;
+  if( ExprHasProperty(p, EP_FromJoin) ) return 0;
+  if( !sqlite3ExprIsInteger(p, &v) ) return 0;
+  return v!=0;
+}
+static int exprAlwaysFalse(Expr *p){
+  int v = 0;
+  if( ExprHasProperty(p, EP_FromJoin) ) return 0;
+  if( !sqlite3ExprIsInteger(p, &v) ) return 0;
+  return v==0;
+}
+
+/*
+** Join two expressions using an AND operator.  If either expression is
+** NULL, then just return the other expression.
+**
+** If one side or the other of the AND is known to be false, then instead
+** of returning an AND expression, just return a constant expression with
+** a value of false.
+*/
+Expr *sqlite3ExprAnd(sqlite3 *db, Expr *pLeft, Expr *pRight){
+  if( pLeft==0 ){
+    return pRight;
+  }else if( pRight==0 ){
+    return pLeft;
+  }else if( exprAlwaysFalse(pLeft) || exprAlwaysFalse(pRight) ){
+    sqlite3ExprDelete(db, pLeft);
+    sqlite3ExprDelete(db, pRight);
+    return sqlite3ExprAlloc(db, TK_INTEGER, &sqlite3IntTokens[0], 0);
+  }else{
+    Expr *pNew = sqlite3ExprAlloc(db, TK_AND, 0, 0);
+    sqlite3ExprAttachSubtrees(db, pNew, pLeft, pRight);
+    return pNew;
+  }
+}
+
+/*
+** Construct a new expression node for a function with multiple
+** arguments.
+*/
+Expr *sqlite3ExprFunction(Parse *pParse, ExprList *pList, Token *pToken){
+  Expr *pNew;
+  sqlite3 *db = pParse->db;
+  assert( pToken );
+  pNew = sqlite3ExprAlloc(db, TK_FUNCTION, pToken, 1);
+  if( pNew==0 ){
+    sqlite3ExprListDelete(db, pList); /* Avoid memory leak when malloc fails */
+    return 0;
+  }
+  pNew->x.pList = pList;
+  assert( !ExprHasProperty(pNew, EP_xIsSelect) );
+  sqlite3ExprSetHeightAndFlags(pParse, pNew);
+  return pNew;
+}
+
+/*
+** Assign a variable number to an expression that encodes a wildcard
+** in the original SQL statement.  
+**
+** Wildcards consisting of a single "?" are assigned the next sequential
+** variable number.
+**
+** Wildcards of the form "?nnn" are assigned the number "nnn".  We make
+** sure "nnn" is not too big to avoid a denial of service attack when
+** the SQL statement comes from an external source.
+**
+** Wildcards of the form ":aaa", "@aaa", or "$aaa" are assigned the same number
+** as the previous instance of the same wildcard.  Or if this is the first
+** instance of the wildcard, the next sequential variable number is
+** assigned.
+*/
+void sqlite3ExprAssignVarNumber(Parse *pParse, Expr *pExpr, u32 n){
+  sqlite3 *db = pParse->db;
+  const char *z;
+  ynVar x;
+
+  if( pExpr==0 ) return;
+  assert( !ExprHasProperty(pExpr, EP_IntValue|EP_Reduced|EP_TokenOnly) );
+  z = pExpr->u.zToken;
+  assert( z!=0 );
+  assert( z[0]!=0 );
+  assert( n==sqlite3Strlen30(z) );
+  if( z[1]==0 ){
+    /* Wildcard of the form "?".  Assign the next variable number */
+    assert( z[0]=='?' );
+    x = (ynVar)(++pParse->nVar);
+  }else{
+    int doAdd = 0;
+    if( z[0]=='?' ){
+      /* Wildcard of the form "?nnn".  Convert "nnn" to an integer and
+      ** use it as the variable number */
+      i64 i;
+      int bOk;
+      if( n==2 ){ /*OPTIMIZATION-IF-TRUE*/
+        i = z[1]-'0';  /* The common case of ?N for a single digit N */
+        bOk = 1;
+      }else{
+        bOk = 0==sqlite3Atoi64(&z[1], &i, n-1, SQLITE_UTF8);
+      }
+      testcase( i==0 );
+      testcase( i==1 );
+      testcase( i==db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER]-1 );
+      testcase( i==db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER] );
+      if( bOk==0 || i<1 || i>db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER] ){
+        sqlite3ErrorMsg(pParse, "variable number must be between ?1 and ?%d",
+            db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER]);
+        return;
+      }
+      x = (ynVar)i;
+      if( x>pParse->nVar ){
+        pParse->nVar = (int)x;
+        doAdd = 1;
+      }else if( sqlite3VListNumToName(pParse->pVList, x)==0 ){
+        doAdd = 1;
+      }
+    }else{
+      /* Wildcards like ":aaa", "$aaa" or "@aaa".  Reuse the same variable
+      ** number as the prior appearance of the same name, or if the name
+      ** has never appeared before, reuse the same variable number
+      */
+      x = (ynVar)sqlite3VListNameToNum(pParse->pVList, z, n);
+      if( x==0 ){
+        x = (ynVar)(++pParse->nVar);
+        doAdd = 1;
+      }
+    }
+    if( doAdd ){
+      pParse->pVList = sqlite3VListAdd(db, pParse->pVList, z, n, x);
+    }
+  }
+  pExpr->iColumn = x;
+  if( x>db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER] ){
+    sqlite3ErrorMsg(pParse, "too many SQL variables");
+  }
+}
+
+/*
+** Recursively delete an expression tree.
+*/
+static SQLITE_NOINLINE void sqlite3ExprDeleteNN(sqlite3 *db, Expr *p){
+  assert( p!=0 );
+  /* Sanity check: Assert that the IntValue is non-negative if it exists */
+  assert( !ExprHasProperty(p, EP_IntValue) || p->u.iValue>=0 );
+#ifdef SQLITE_DEBUG
+  if( ExprHasProperty(p, EP_Leaf) && !ExprHasProperty(p, EP_TokenOnly) ){
+    assert( p->pLeft==0 );
+    assert( p->pRight==0 );
+    assert( p->x.pSelect==0 );
+  }
+#endif
+  if( !ExprHasProperty(p, (EP_TokenOnly|EP_Leaf)) ){
+    /* The Expr.x union is never used at the same time as Expr.pRight */
+    assert( p->x.pList==0 || p->pRight==0 );
+    if( p->pLeft && p->op!=TK_SELECT_COLUMN ) sqlite3ExprDeleteNN(db, p->pLeft);
+    sqlite3ExprDelete(db, p->pRight);
+    if( ExprHasProperty(p, EP_xIsSelect) ){
+      sqlite3SelectDelete(db, p->x.pSelect);
+    }else{
+      sqlite3ExprListDelete(db, p->x.pList);
+    }
+  }
+  if( ExprHasProperty(p, EP_MemToken) ) sqlite3DbFree(db, p->u.zToken);
+  if( !ExprHasProperty(p, EP_Static) ){
+    sqlite3DbFree(db, p);
+  }
+}
+void sqlite3ExprDelete(sqlite3 *db, Expr *p){
+  if( p ) sqlite3ExprDeleteNN(db, p);
+}
+
+/*
+** Return the number of bytes allocated for the expression structure 
+** passed as the first argument. This is always one of EXPR_FULLSIZE,
+** EXPR_REDUCEDSIZE or EXPR_TOKENONLYSIZE.
+*/
+static int exprStructSize(Expr *p){
+  if( ExprHasProperty(p, EP_TokenOnly) ) return EXPR_TOKENONLYSIZE;
+  if( ExprHasProperty(p, EP_Reduced) ) return EXPR_REDUCEDSIZE;
+  return EXPR_FULLSIZE;
+}
+
+/*
+** The dupedExpr*Size() routines each return the number of bytes required
+** to store a copy of an expression or expression tree.  They differ in
+** how much of the tree is measured.
+**
+**     dupedExprStructSize()     Size of only the Expr structure 
+**     dupedExprNodeSize()       Size of Expr + space for token
+**     dupedExprSize()           Expr + token + subtree components
+**
+***************************************************************************
+**
+** The dupedExprStructSize() function returns two values OR-ed together:  
+** (1) the space required for a copy of the Expr structure only and 
+** (2) the EP_xxx flags that indicate what the structure size should be.
+** The return values is always one of:
+**
+**      EXPR_FULLSIZE
+**      EXPR_REDUCEDSIZE   | EP_Reduced
+**      EXPR_TOKENONLYSIZE | EP_TokenOnly
+**
+** The size of the structure can be found by masking the return value
+** of this routine with 0xfff.  The flags can be found by masking the
+** return value with EP_Reduced|EP_TokenOnly.
+**
+** Note that with flags==EXPRDUP_REDUCE, this routines works on full-size
+** (unreduced) Expr objects as they or originally constructed by the parser.
+** During expression analysis, extra information is computed and moved into
+** later parts of teh Expr object and that extra information might get chopped
+** off if the expression is reduced.  Note also that it does not work to
+** make an EXPRDUP_REDUCE copy of a reduced expression.  It is only legal
+** to reduce a pristine expression tree from the parser.  The implementation
+** of dupedExprStructSize() contain multiple assert() statements that attempt
+** to enforce this constraint.
+*/
+static int dupedExprStructSize(Expr *p, int flags){
+  int nSize;
+  assert( flags==EXPRDUP_REDUCE || flags==0 ); /* Only one flag value allowed */
+  assert( EXPR_FULLSIZE<=0xfff );
+  assert( (0xfff & (EP_Reduced|EP_TokenOnly))==0 );
+  if( 0==flags || p->op==TK_SELECT_COLUMN ){
+    nSize = EXPR_FULLSIZE;
+  }else{
+    assert( !ExprHasProperty(p, EP_TokenOnly|EP_Reduced) );
+    assert( !ExprHasProperty(p, EP_FromJoin) ); 
+    assert( !ExprHasProperty(p, EP_MemToken) );
+    assert( !ExprHasProperty(p, EP_NoReduce) );
+    if( p->pLeft || p->x.pList ){
+      nSize = EXPR_REDUCEDSIZE | EP_Reduced;
+    }else{
+      assert( p->pRight==0 );
+      nSize = EXPR_TOKENONLYSIZE | EP_TokenOnly;
+    }
+  }
+  return nSize;
+}
+
+/*
+** This function returns the space in bytes required to store the copy 
+** of the Expr structure and a copy of the Expr.u.zToken string (if that
+** string is defined.)
+*/
+static int dupedExprNodeSize(Expr *p, int flags){
+  int nByte = dupedExprStructSize(p, flags) & 0xfff;
+  if( !ExprHasProperty(p, EP_IntValue) && p->u.zToken ){
+    nByte += sqlite3Strlen30(p->u.zToken)+1;
+  }
+  return ROUND8(nByte);
+}
+
+/*
+** Return the number of bytes required to create a duplicate of the 
+** expression passed as the first argument. The second argument is a
+** mask containing EXPRDUP_XXX flags.
+**
+** The value returned includes space to create a copy of the Expr struct
+** itself and the buffer referred to by Expr.u.zToken, if any.
+**
+** If the EXPRDUP_REDUCE flag is set, then the return value includes 
+** space to duplicate all Expr nodes in the tree formed by Expr.pLeft 
+** and Expr.pRight variables (but not for any structures pointed to or 
+** descended from the Expr.x.pList or Expr.x.pSelect variables).
+*/
+static int dupedExprSize(Expr *p, int flags){
+  int nByte = 0;
+  if( p ){
+    nByte = dupedExprNodeSize(p, flags);
+    if( flags&EXPRDUP_REDUCE ){
+      nByte += dupedExprSize(p->pLeft, flags) + dupedExprSize(p->pRight, flags);
+    }
+  }
+  return nByte;
+}
+
+/*
+** This function is similar to sqlite3ExprDup(), except that if pzBuffer 
+** is not NULL then *pzBuffer is assumed to point to a buffer large enough 
+** to store the copy of expression p, the copies of p->u.zToken
+** (if applicable), and the copies of the p->pLeft and p->pRight expressions,
+** if any. Before returning, *pzBuffer is set to the first byte past the
+** portion of the buffer copied into by this function.
+*/
+static Expr *exprDup(sqlite3 *db, Expr *p, int dupFlags, u8 **pzBuffer){
+  Expr *pNew;           /* Value to return */
+  u8 *zAlloc;           /* Memory space from which to build Expr object */
+  u32 staticFlag;       /* EP_Static if space not obtained from malloc */
+
+  assert( db!=0 );
+  assert( p );
+  assert( dupFlags==0 || dupFlags==EXPRDUP_REDUCE );
+  assert( pzBuffer==0 || dupFlags==EXPRDUP_REDUCE );
+
+  /* Figure out where to write the new Expr structure. */
+  if( pzBuffer ){
+    zAlloc = *pzBuffer;
+    staticFlag = EP_Static;
+  }else{
+    zAlloc = sqlite3DbMallocRawNN(db, dupedExprSize(p, dupFlags));
+    staticFlag = 0;
+  }
+  pNew = (Expr *)zAlloc;
+
+  if( pNew ){
+    /* Set nNewSize to the size allocated for the structure pointed to
+    ** by pNew. This is either EXPR_FULLSIZE, EXPR_REDUCEDSIZE or
+    ** EXPR_TOKENONLYSIZE. nToken is set to the number of bytes consumed
+    ** by the copy of the p->u.zToken string (if any).
+    */
+    const unsigned nStructSize = dupedExprStructSize(p, dupFlags);
+    const int nNewSize = nStructSize & 0xfff;
+    int nToken;
+    if( !ExprHasProperty(p, EP_IntValue) && p->u.zToken ){
+      nToken = sqlite3Strlen30(p->u.zToken) + 1;
+    }else{
+      nToken = 0;
+    }
+    if( dupFlags ){
+      assert( ExprHasProperty(p, EP_Reduced)==0 );
+      memcpy(zAlloc, p, nNewSize);
+    }else{
+      u32 nSize = (u32)exprStructSize(p);
+      memcpy(zAlloc, p, nSize);
+      if( nSize<EXPR_FULLSIZE ){ 
+        memset(&zAlloc[nSize], 0, EXPR_FULLSIZE-nSize);
+      }
+    }
+
+    /* Set the EP_Reduced, EP_TokenOnly, and EP_Static flags appropriately. */
+    pNew->flags &= ~(EP_Reduced|EP_TokenOnly|EP_Static|EP_MemToken);
+    pNew->flags |= nStructSize & (EP_Reduced|EP_TokenOnly);
+    pNew->flags |= staticFlag;
+
+    /* Copy the p->u.zToken string, if any. */
+    if( nToken ){
+      char *zToken = pNew->u.zToken = (char*)&zAlloc[nNewSize];
+      memcpy(zToken, p->u.zToken, nToken);
+    }
+
+    if( 0==((p->flags|pNew->flags) & (EP_TokenOnly|EP_Leaf)) ){
+      /* Fill in the pNew->x.pSelect or pNew->x.pList member. */
+      if( ExprHasProperty(p, EP_xIsSelect) ){
+        pNew->x.pSelect = sqlite3SelectDup(db, p->x.pSelect, dupFlags);
+      }else{
+        pNew->x.pList = sqlite3ExprListDup(db, p->x.pList, dupFlags);
+      }
+    }
+
+    /* Fill in pNew->pLeft and pNew->pRight. */
+    if( ExprHasProperty(pNew, EP_Reduced|EP_TokenOnly) ){
+      zAlloc += dupedExprNodeSize(p, dupFlags);
+      if( !ExprHasProperty(pNew, EP_TokenOnly|EP_Leaf) ){
+        pNew->pLeft = p->pLeft ?
+                      exprDup(db, p->pLeft, EXPRDUP_REDUCE, &zAlloc) : 0;
+        pNew->pRight = p->pRight ?
+                       exprDup(db, p->pRight, EXPRDUP_REDUCE, &zAlloc) : 0;
+      }
+      if( pzBuffer ){
+        *pzBuffer = zAlloc;
+      }
+    }else{
+      if( !ExprHasProperty(p, EP_TokenOnly|EP_Leaf) ){
+        if( pNew->op==TK_SELECT_COLUMN ){
+          pNew->pLeft = p->pLeft;
+          assert( p->iColumn==0 || p->pRight==0 );
+          assert( p->pRight==0  || p->pRight==p->pLeft );
+        }else{
+          pNew->pLeft = sqlite3ExprDup(db, p->pLeft, 0);
+        }
+        pNew->pRight = sqlite3ExprDup(db, p->pRight, 0);
+      }
+    }
+  }
+  return pNew;
+}
+
+/*
+** Create and return a deep copy of the object passed as the second 
+** argument. If an OOM condition is encountered, NULL is returned
+** and the db->mallocFailed flag set.
+*/
+#ifndef SQLITE_OMIT_CTE
+static With *withDup(sqlite3 *db, With *p){
+  With *pRet = 0;
+  if( p ){
+    int nByte = sizeof(*p) + sizeof(p->a[0]) * (p->nCte-1);
+    pRet = sqlite3DbMallocZero(db, nByte);
+    if( pRet ){
+      int i;
+      pRet->nCte = p->nCte;
+      for(i=0; i<p->nCte; i++){
+        pRet->a[i].pSelect = sqlite3SelectDup(db, p->a[i].pSelect, 0);
+        pRet->a[i].pCols = sqlite3ExprListDup(db, p->a[i].pCols, 0);
+        pRet->a[i].zName = sqlite3DbStrDup(db, p->a[i].zName);
+      }
+    }
+  }
+  return pRet;
+}
+#else
+# define withDup(x,y) 0
+#endif
+
+/*
+** The following group of routines make deep copies of expressions,
+** expression lists, ID lists, and select statements.  The copies can
+** be deleted (by being passed to their respective ...Delete() routines)
+** without effecting the originals.
+**
+** The expression list, ID, and source lists return by sqlite3ExprListDup(),
+** sqlite3IdListDup(), and sqlite3SrcListDup() can not be further expanded 
+** by subsequent calls to sqlite*ListAppend() routines.
+**
+** Any tables that the SrcList might point to are not duplicated.
+**
+** The flags parameter contains a combination of the EXPRDUP_XXX flags.
+** If the EXPRDUP_REDUCE flag is set, then the structure returned is a
+** truncated version of the usual Expr structure that will be stored as
+** part of the in-memory representation of the database schema.
+*/
+Expr *sqlite3ExprDup(sqlite3 *db, Expr *p, int flags){
+  assert( flags==0 || flags==EXPRDUP_REDUCE );
+  return p ? exprDup(db, p, flags, 0) : 0;
+}
+ExprList *sqlite3ExprListDup(sqlite3 *db, ExprList *p, int flags){
+  ExprList *pNew;
+  struct ExprList_item *pItem, *pOldItem;
+  int i;
+  Expr *pPriorSelectCol = 0;
+  assert( db!=0 );
+  if( p==0 ) return 0;
+  pNew = sqlite3DbMallocRawNN(db, sizeof(*pNew) );
+  if( pNew==0 ) return 0;
+  pNew->nExpr = i = p->nExpr;
+  if( (flags & EXPRDUP_REDUCE)==0 ) for(i=1; i<p->nExpr; i+=i){}
+  pNew->a = pItem = sqlite3DbMallocRawNN(db,  i*sizeof(p->a[0]) );
+  if( pItem==0 ){
+    sqlite3DbFree(db, pNew);
+    return 0;
+  } 
+  pOldItem = p->a;
+  for(i=0; i<p->nExpr; i++, pItem++, pOldItem++){
+    Expr *pOldExpr = pOldItem->pExpr;
+    Expr *pNewExpr;
+    pItem->pExpr = sqlite3ExprDup(db, pOldExpr, flags);
+    if( pOldExpr 
+     && pOldExpr->op==TK_SELECT_COLUMN
+     && (pNewExpr = pItem->pExpr)!=0 
+    ){
+      assert( pNewExpr->iColumn==0 || i>0 );
+      if( pNewExpr->iColumn==0 ){
+        assert( pOldExpr->pLeft==pOldExpr->pRight );
+        pPriorSelectCol = pNewExpr->pLeft = pNewExpr->pRight;
+      }else{
+        assert( i>0 );
+        assert( pItem[-1].pExpr!=0 );
+        assert( pNewExpr->iColumn==pItem[-1].pExpr->iColumn+1 );
+        assert( pPriorSelectCol==pItem[-1].pExpr->pLeft );
+        pNewExpr->pLeft = pPriorSelectCol;
+      }
+    }
+    pItem->zName = sqlite3DbStrDup(db, pOldItem->zName);
+    pItem->zSpan = sqlite3DbStrDup(db, pOldItem->zSpan);
+    pItem->sortOrder = pOldItem->sortOrder;
+    pItem->done = 0;
+    pItem->bSpanIsTab = pOldItem->bSpanIsTab;
+    pItem->u = pOldItem->u;
+  }
+  return pNew;
+}
+
+/*
+** If cursors, triggers, views and subqueries are all omitted from
+** the build, then none of the following routines, except for 
+** sqlite3SelectDup(), can be called. sqlite3SelectDup() is sometimes
+** called with a NULL argument.
+*/
+#if !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_TRIGGER) \
+ || !defined(SQLITE_OMIT_SUBQUERY)
+SrcList *sqlite3SrcListDup(sqlite3 *db, SrcList *p, int flags){
+  SrcList *pNew;
+  int i;
+  int nByte;
+  assert( db!=0 );
+  if( p==0 ) return 0;
+  nByte = sizeof(*p) + (p->nSrc>0 ? sizeof(p->a[0]) * (p->nSrc-1) : 0);
+  pNew = sqlite3DbMallocRawNN(db, nByte );
+  if( pNew==0 ) return 0;
+  pNew->nSrc = pNew->nAlloc = p->nSrc;
+  for(i=0; i<p->nSrc; i++){
+    struct SrcList_item *pNewItem = &pNew->a[i];
+    struct SrcList_item *pOldItem = &p->a[i];
+    Table *pTab;
+    pNewItem->pSchema = pOldItem->pSchema;
+    pNewItem->zDatabase = sqlite3DbStrDup(db, pOldItem->zDatabase);
+    pNewItem->zName = sqlite3DbStrDup(db, pOldItem->zName);
+    pNewItem->zAlias = sqlite3DbStrDup(db, pOldItem->zAlias);
+    pNewItem->fg = pOldItem->fg;
+    pNewItem->iCursor = pOldItem->iCursor;
+    pNewItem->addrFillSub = pOldItem->addrFillSub;
+    pNewItem->regReturn = pOldItem->regReturn;
+    if( pNewItem->fg.isIndexedBy ){
+      pNewItem->u1.zIndexedBy = sqlite3DbStrDup(db, pOldItem->u1.zIndexedBy);
+    }
+    pNewItem->pIBIndex = pOldItem->pIBIndex;
+    if( pNewItem->fg.isTabFunc ){
+      pNewItem->u1.pFuncArg = 
+          sqlite3ExprListDup(db, pOldItem->u1.pFuncArg, flags);
+    }
+    pTab = pNewItem->pTab = pOldItem->pTab;
+    if( pTab ){
+      pTab->nTabRef++;
+    }
+    pNewItem->pSelect = sqlite3SelectDup(db, pOldItem->pSelect, flags);
+    pNewItem->pOn = sqlite3ExprDup(db, pOldItem->pOn, flags);
+    pNewItem->pUsing = sqlite3IdListDup(db, pOldItem->pUsing);
+    pNewItem->colUsed = pOldItem->colUsed;
+  }
+  return pNew;
+}
+IdList *sqlite3IdListDup(sqlite3 *db, IdList *p){
+  IdList *pNew;
+  int i;
+  assert( db!=0 );
+  if( p==0 ) return 0;
+  pNew = sqlite3DbMallocRawNN(db, sizeof(*pNew) );
+  if( pNew==0 ) return 0;
+  pNew->nId = p->nId;
+  pNew->a = sqlite3DbMallocRawNN(db, p->nId*sizeof(p->a[0]) );
+  if( pNew->a==0 ){
+    sqlite3DbFree(db, pNew);
+    return 0;
+  }
+  /* Note that because the size of the allocation for p->a[] is not
+  ** necessarily a power of two, sqlite3IdListAppend() may not be called
+  ** on the duplicate created by this function. */
+  for(i=0; i<p->nId; i++){
+    struct IdList_item *pNewItem = &pNew->a[i];
+    struct IdList_item *pOldItem = &p->a[i];
+    pNewItem->zName = sqlite3DbStrDup(db, pOldItem->zName);
+    pNewItem->idx = pOldItem->idx;
+  }
+  return pNew;
+}
+Select *sqlite3SelectDup(sqlite3 *db, Select *pDup, int flags){
+  Select *pRet = 0;
+  Select *pNext = 0;
+  Select **pp = &pRet;
+  Select *p;
+
+  assert( db!=0 );
+  for(p=pDup; p; p=p->pPrior){
+    Select *pNew = sqlite3DbMallocRawNN(db, sizeof(*p) );
+    if( pNew==0 ) break;
+    pNew->pEList = sqlite3ExprListDup(db, p->pEList, flags);
+    pNew->pSrc = sqlite3SrcListDup(db, p->pSrc, flags);
+    pNew->pWhere = sqlite3ExprDup(db, p->pWhere, flags);
+    pNew->pGroupBy = sqlite3ExprListDup(db, p->pGroupBy, flags);
+    pNew->pHaving = sqlite3ExprDup(db, p->pHaving, flags);
+    pNew->pOrderBy = sqlite3ExprListDup(db, p->pOrderBy, flags);
+    pNew->op = p->op;
+    pNew->pNext = pNext;
+    pNew->pPrior = 0;
+    pNew->pLimit = sqlite3ExprDup(db, p->pLimit, flags);
+    pNew->pOffset = sqlite3ExprDup(db, p->pOffset, flags);
+    pNew->iLimit = 0;
+    pNew->iOffset = 0;
+    pNew->selFlags = p->selFlags & ~SF_UsesEphemeral;
+    pNew->addrOpenEphm[0] = -1;
+    pNew->addrOpenEphm[1] = -1;
+    pNew->nSelectRow = p->nSelectRow;
+    pNew->pWith = withDup(db, p->pWith);
+    sqlite3SelectSetName(pNew, p->zSelName);
+    *pp = pNew;
+    pp = &pNew->pPrior;
+    pNext = pNew;
+  }
+
+  return pRet;
+}
+#else
+Select *sqlite3SelectDup(sqlite3 *db, Select *p, int flags){
+  assert( p==0 );
+  return 0;
+}
+#endif
+
+
+/*
+** Add a new element to the end of an expression list.  If pList is
+** initially NULL, then create a new expression list.
+**
+** If a memory allocation error occurs, the entire list is freed and
+** NULL is returned.  If non-NULL is returned, then it is guaranteed
+** that the new entry was successfully appended.
+*/
+ExprList *sqlite3ExprListAppend(
+  Parse *pParse,          /* Parsing context */
+  ExprList *pList,        /* List to which to append. Might be NULL */
+  Expr *pExpr             /* Expression to be appended. Might be NULL */
+){
+  sqlite3 *db = pParse->db;
+  assert( db!=0 );
+  if( pList==0 ){
+    pList = sqlite3DbMallocRawNN(db, sizeof(ExprList) );
+    if( pList==0 ){
+      goto no_mem;
+    }
+    pList->nExpr = 0;
+    pList->a = sqlite3DbMallocRawNN(db, sizeof(pList->a[0]));
+    if( pList->a==0 ) goto no_mem;
+  }else if( (pList->nExpr & (pList->nExpr-1))==0 ){
+    struct ExprList_item *a;
+    assert( pList->nExpr>0 );
+    a = sqlite3DbRealloc(db, pList->a, pList->nExpr*2*sizeof(pList->a[0]));
+    if( a==0 ){
+      goto no_mem;
+    }
+    pList->a = a;
+  }
+  assert( pList->a!=0 );
+  if( 1 ){
+    struct ExprList_item *pItem = &pList->a[pList->nExpr++];
+    memset(pItem, 0, sizeof(*pItem));
+    pItem->pExpr = pExpr;
+  }
+  return pList;
+
+no_mem:     
+  /* Avoid leaking memory if malloc has failed. */
+  sqlite3ExprDelete(db, pExpr);
+  sqlite3ExprListDelete(db, pList);
+  return 0;
+}
+
+/*
+** pColumns and pExpr form a vector assignment which is part of the SET
+** clause of an UPDATE statement.  Like this:
+**
+**        (a,b,c) = (expr1,expr2,expr3)
+** Or:    (a,b,c) = (SELECT x,y,z FROM ....)
+**
+** For each term of the vector assignment, append new entries to the
+** expression list pList.  In the case of a subquery on the RHS, append
+** TK_SELECT_COLUMN expressions.
+*/
+ExprList *sqlite3ExprListAppendVector(
+  Parse *pParse,         /* Parsing context */
+  ExprList *pList,       /* List to which to append. Might be NULL */
+  IdList *pColumns,      /* List of names of LHS of the assignment */
+  Expr *pExpr            /* Vector expression to be appended. Might be NULL */
+){
+  sqlite3 *db = pParse->db;
+  int n;
+  int i;
+  int iFirst = pList ? pList->nExpr : 0;
+  /* pColumns can only be NULL due to an OOM but an OOM will cause an
+  ** exit prior to this routine being invoked */
+  if( NEVER(pColumns==0) ) goto vector_append_error;
+  if( pExpr==0 ) goto vector_append_error;
+
+  /* If the RHS is a vector, then we can immediately check to see that 
+  ** the size of the RHS and LHS match.  But if the RHS is a SELECT, 
+  ** wildcards ("*") in the result set of the SELECT must be expanded before
+  ** we can do the size check, so defer the size check until code generation.
+  */
+  if( pExpr->op!=TK_SELECT && pColumns->nId!=(n=sqlite3ExprVectorSize(pExpr)) ){
+    sqlite3ErrorMsg(pParse, "%d columns assigned %d values",
+                    pColumns->nId, n);
+    goto vector_append_error;
+  }
+
+  for(i=0; i<pColumns->nId; i++){
+    Expr *pSubExpr = sqlite3ExprForVectorField(pParse, pExpr, i);
+    pList = sqlite3ExprListAppend(pParse, pList, pSubExpr);
+    if( pList ){
+      assert( pList->nExpr==iFirst+i+1 );
+      pList->a[pList->nExpr-1].zName = pColumns->a[i].zName;
+      pColumns->a[i].zName = 0;
+    }
+  }
+
+  if( pExpr->op==TK_SELECT ){
+    if( pList && pList->a[iFirst].pExpr ){
+      Expr *pFirst = pList->a[iFirst].pExpr;
+      assert( pFirst->op==TK_SELECT_COLUMN );
+     
+      /* Store the SELECT statement in pRight so it will be deleted when
+      ** sqlite3ExprListDelete() is called */
+      pFirst->pRight = pExpr;
+      pExpr = 0;
+
+      /* Remember the size of the LHS in iTable so that we can check that
+      ** the RHS and LHS sizes match during code generation. */
+      pFirst->iTable = pColumns->nId;
+    }
+  }
+
+vector_append_error:
+  sqlite3ExprDelete(db, pExpr);
+  sqlite3IdListDelete(db, pColumns);
+  return pList;
+}
+
+/*
+** Set the sort order for the last element on the given ExprList.
+*/
+void sqlite3ExprListSetSortOrder(ExprList *p, int iSortOrder){
+  if( p==0 ) return;
+  assert( SQLITE_SO_UNDEFINED<0 && SQLITE_SO_ASC>=0 && SQLITE_SO_DESC>0 );
+  assert( p->nExpr>0 );
+  if( iSortOrder<0 ){
+    assert( p->a[p->nExpr-1].sortOrder==SQLITE_SO_ASC );
+    return;
+  }
+  p->a[p->nExpr-1].sortOrder = (u8)iSortOrder;
+}
+
+/*
+** Set the ExprList.a[].zName element of the most recently added item
+** on the expression list.
+**
+** pList might be NULL following an OOM error.  But pName should never be
+** NULL.  If a memory allocation fails, the pParse->db->mallocFailed flag
+** is set.
+*/
+void sqlite3ExprListSetName(
+  Parse *pParse,          /* Parsing context */
+  ExprList *pList,        /* List to which to add the span. */
+  Token *pName,           /* Name to be added */
+  int dequote             /* True to cause the name to be dequoted */
+){
+  assert( pList!=0 || pParse->db->mallocFailed!=0 );
+  if( pList ){
+    struct ExprList_item *pItem;
+    assert( pList->nExpr>0 );
+    pItem = &pList->a[pList->nExpr-1];
+    assert( pItem->zName==0 );
+    pItem->zName = sqlite3DbStrNDup(pParse->db, pName->z, pName->n);
+    if( dequote ) sqlite3Dequote(pItem->zName);
+  }
+}
+
+/*
+** Set the ExprList.a[].zSpan element of the most recently added item
+** on the expression list.
+**
+** pList might be NULL following an OOM error.  But pSpan should never be
+** NULL.  If a memory allocation fails, the pParse->db->mallocFailed flag
+** is set.
+*/
+void sqlite3ExprListSetSpan(
+  Parse *pParse,          /* Parsing context */
+  ExprList *pList,        /* List to which to add the span. */
+  ExprSpan *pSpan         /* The span to be added */
+){
+  sqlite3 *db = pParse->db;
+  assert( pList!=0 || db->mallocFailed!=0 );
+  if( pList ){
+    struct ExprList_item *pItem = &pList->a[pList->nExpr-1];
+    assert( pList->nExpr>0 );
+    assert( db->mallocFailed || pItem->pExpr==pSpan->pExpr );
+    sqlite3DbFree(db, pItem->zSpan);
+    pItem->zSpan = sqlite3DbStrNDup(db, (char*)pSpan->zStart,
+                                    (int)(pSpan->zEnd - pSpan->zStart));
+  }
+}
+
+/*
+** If the expression list pEList contains more than iLimit elements,
+** leave an error message in pParse.
+*/
+void sqlite3ExprListCheckLength(
+  Parse *pParse,
+  ExprList *pEList,
+  const char *zObject
+){
+  int mx = pParse->db->aLimit[SQLITE_LIMIT_COLUMN];
+  testcase( pEList && pEList->nExpr==mx );
+  testcase( pEList && pEList->nExpr==mx+1 );
+  if( pEList && pEList->nExpr>mx ){
+    sqlite3ErrorMsg(pParse, "too many columns in %s", zObject);
+  }
+}
+
+/*
+** Delete an entire expression list.
+*/
+static SQLITE_NOINLINE void exprListDeleteNN(sqlite3 *db, ExprList *pList){
+  int i;
+  struct ExprList_item *pItem;
+  assert( pList->a!=0 || pList->nExpr==0 );
+  for(pItem=pList->a, i=0; i<pList->nExpr; i++, pItem++){
+    sqlite3ExprDelete(db, pItem->pExpr);
+    sqlite3DbFree(db, pItem->zName);
+    sqlite3DbFree(db, pItem->zSpan);
+  }
+  sqlite3DbFree(db, pList->a);
+  sqlite3DbFree(db, pList);
+}
+void sqlite3ExprListDelete(sqlite3 *db, ExprList *pList){
+  if( pList ) exprListDeleteNN(db, pList);
+}
+
+/*
+** Return the bitwise-OR of all Expr.flags fields in the given
+** ExprList.
+*/
+u32 sqlite3ExprListFlags(const ExprList *pList){
+  int i;
+  u32 m = 0;
+  if( pList ){
+    for(i=0; i<pList->nExpr; i++){
+       Expr *pExpr = pList->a[i].pExpr;
+       assert( pExpr!=0 );
+       m |= pExpr->flags;
+    }
+  }
+  return m;
+}
+
+/*
+** These routines are Walker callbacks used to check expressions to
+** see if they are "constant" for some definition of constant.  The
+** Walker.eCode value determines the type of "constant" we are looking
+** for.
+**
+** These callback routines are used to implement the following:
+**
+**     sqlite3ExprIsConstant()                  pWalker->eCode==1
+**     sqlite3ExprIsConstantNotJoin()           pWalker->eCode==2
+**     sqlite3ExprIsTableConstant()             pWalker->eCode==3
+**     sqlite3ExprIsConstantOrFunction()        pWalker->eCode==4 or 5
+**
+** In all cases, the callbacks set Walker.eCode=0 and abort if the expression
+** is found to not be a constant.
+**
+** The sqlite3ExprIsConstantOrFunction() is used for evaluating expressions
+** in a CREATE TABLE statement.  The Walker.eCode value is 5 when parsing
+** an existing schema and 4 when processing a new statement.  A bound
+** parameter raises an error for new statements, but is silently converted
+** to NULL for existing schemas.  This allows sqlite_master tables that 
+** contain a bound parameter because they were generated by older versions
+** of SQLite to be parsed by newer versions of SQLite without raising a
+** malformed schema error.
+*/
+static int exprNodeIsConstant(Walker *pWalker, Expr *pExpr){
+
+  /* If pWalker->eCode is 2 then any term of the expression that comes from
+  ** the ON or USING clauses of a left join disqualifies the expression
+  ** from being considered constant. */
+  if( pWalker->eCode==2 && ExprHasProperty(pExpr, EP_FromJoin) ){
+    pWalker->eCode = 0;
+    return WRC_Abort;
+  }
+
+  switch( pExpr->op ){
+    /* Consider functions to be constant if all their arguments are constant
+    ** and either pWalker->eCode==4 or 5 or the function has the
+    ** SQLITE_FUNC_CONST flag. */
+    case TK_FUNCTION:
+      if( pWalker->eCode>=4 || ExprHasProperty(pExpr,EP_ConstFunc) ){
+        return WRC_Continue;
+      }else{
+        pWalker->eCode = 0;
+        return WRC_Abort;
+      }
+    case TK_ID:
+    case TK_COLUMN:
+    case TK_AGG_FUNCTION:
+    case TK_AGG_COLUMN:
+      testcase( pExpr->op==TK_ID );
+      testcase( pExpr->op==TK_COLUMN );
+      testcase( pExpr->op==TK_AGG_FUNCTION );
+      testcase( pExpr->op==TK_AGG_COLUMN );
+      if( pWalker->eCode==3 && pExpr->iTable==pWalker->u.iCur ){
+        return WRC_Continue;
+      }else{
+        pWalker->eCode = 0;
+        return WRC_Abort;
+      }
+    case TK_VARIABLE:
+      if( pWalker->eCode==5 ){
+        /* Silently convert bound parameters that appear inside of CREATE
+        ** statements into a NULL when parsing the CREATE statement text out
+        ** of the sqlite_master table */
+        pExpr->op = TK_NULL;
+      }else if( pWalker->eCode==4 ){
+        /* A bound parameter in a CREATE statement that originates from
+        ** sqlite3_prepare() causes an error */
+        pWalker->eCode = 0;
+        return WRC_Abort;
+      }
+      /* Fall through */
+    default:
+      testcase( pExpr->op==TK_SELECT ); /* selectNodeIsConstant will disallow */
+      testcase( pExpr->op==TK_EXISTS ); /* selectNodeIsConstant will disallow */
+      return WRC_Continue;
+  }
+}
+static int selectNodeIsConstant(Walker *pWalker, Select *NotUsed){
+  UNUSED_PARAMETER(NotUsed);
+  pWalker->eCode = 0;
+  return WRC_Abort;
+}
+static int exprIsConst(Expr *p, int initFlag, int iCur){
+  Walker w;
+  memset(&w, 0, sizeof(w));
+  w.eCode = initFlag;
+  w.xExprCallback = exprNodeIsConstant;
+  w.xSelectCallback = selectNodeIsConstant;
+  w.u.iCur = iCur;
+  sqlite3WalkExpr(&w, p);
+  return w.eCode;
+}
+
+/*
+** Walk an expression tree.  Return non-zero if the expression is constant
+** and 0 if it involves variables or function calls.
+**
+** For the purposes of this function, a double-quoted string (ex: "abc")
+** is considered a variable but a single-quoted string (ex: 'abc') is
+** a constant.
+*/
+int sqlite3ExprIsConstant(Expr *p){
+  return exprIsConst(p, 1, 0);
+}
+
+/*
+** Walk an expression tree.  Return non-zero if the expression is constant
+** that does no originate from the ON or USING clauses of a join.
+** Return 0 if it involves variables or function calls or terms from
+** an ON or USING clause.
+*/
+int sqlite3ExprIsConstantNotJoin(Expr *p){
+  return exprIsConst(p, 2, 0);
+}
+
+/*
+** Walk an expression tree.  Return non-zero if the expression is constant
+** for any single row of the table with cursor iCur.  In other words, the
+** expression must not refer to any non-deterministic function nor any
+** table other than iCur.
+*/
+int sqlite3ExprIsTableConstant(Expr *p, int iCur){
+  return exprIsConst(p, 3, iCur);
+}
+
+/*
+** Walk an expression tree.  Return non-zero if the expression is constant
+** or a function call with constant arguments.  Return and 0 if there
+** are any variables.
+**
+** For the purposes of this function, a double-quoted string (ex: "abc")
+** is considered a variable but a single-quoted string (ex: 'abc') is
+** a constant.
+*/
+int sqlite3ExprIsConstantOrFunction(Expr *p, u8 isInit){
+  assert( isInit==0 || isInit==1 );
+  return exprIsConst(p, 4+isInit, 0);
+}
+
+#ifdef SQLITE_ENABLE_CURSOR_HINTS
+/*
+** Walk an expression tree.  Return 1 if the expression contains a
+** subquery of some kind.  Return 0 if there are no subqueries.
+*/
+int sqlite3ExprContainsSubquery(Expr *p){
+  Walker w;
+  memset(&w, 0, sizeof(w));
+  w.eCode = 1;
+  w.xExprCallback = sqlite3ExprWalkNoop;
+  w.xSelectCallback = selectNodeIsConstant;
+  sqlite3WalkExpr(&w, p);
+  return w.eCode==0;
+}
+#endif
+
+/*
+** If the expression p codes a constant integer that is small enough
+** to fit in a 32-bit integer, return 1 and put the value of the integer
+** in *pValue.  If the expression is not an integer or if it is too big
+** to fit in a signed 32-bit integer, return 0 and leave *pValue unchanged.
+*/
+int sqlite3ExprIsInteger(Expr *p, int *pValue){
+  int rc = 0;
+
+  /* If an expression is an integer literal that fits in a signed 32-bit
+  ** integer, then the EP_IntValue flag will have already been set */
+  assert( p->op!=TK_INTEGER || (p->flags & EP_IntValue)!=0
+           || sqlite3GetInt32(p->u.zToken, &rc)==0 );
+
+  if( p->flags & EP_IntValue ){
+    *pValue = p->u.iValue;
+    return 1;
+  }
+  switch( p->op ){
+    case TK_UPLUS: {
+      rc = sqlite3ExprIsInteger(p->pLeft, pValue);
+      break;
+    }
+    case TK_UMINUS: {
+      int v;
+      if( sqlite3ExprIsInteger(p->pLeft, &v) ){
+        assert( v!=(-2147483647-1) );
+        *pValue = -v;
+        rc = 1;
+      }
+      break;
+    }
+    default: break;
+  }
+  return rc;
+}
+
+/*
+** Return FALSE if there is no chance that the expression can be NULL.
+**
+** If the expression might be NULL or if the expression is too complex
+** to tell return TRUE.  
+**
+** This routine is used as an optimization, to skip OP_IsNull opcodes
+** when we know that a value cannot be NULL.  Hence, a false positive
+** (returning TRUE when in fact the expression can never be NULL) might
+** be a small performance hit but is otherwise harmless.  On the other
+** hand, a false negative (returning FALSE when the result could be NULL)
+** will likely result in an incorrect answer.  So when in doubt, return
+** TRUE.
+*/
+int sqlite3ExprCanBeNull(const Expr *p){
+  u8 op;
+  while( p->op==TK_UPLUS || p->op==TK_UMINUS ){ p = p->pLeft; }
+  op = p->op;
+  if( op==TK_REGISTER ) op = p->op2;
+  switch( op ){
+    case TK_INTEGER:
+    case TK_STRING:
+    case TK_FLOAT:
+    case TK_BLOB:
+      return 0;
+    case TK_COLUMN:
+      assert( p->pTab!=0 );
+      return ExprHasProperty(p, EP_CanBeNull) ||
+             (p->iColumn>=0 && p->pTab->aCol[p->iColumn].notNull==0);
+    default:
+      return 1;
+  }
+}
+
+/*
+** Return TRUE if the given expression is a constant which would be
+** unchanged by OP_Affinity with the affinity given in the second
+** argument.
+**
+** This routine is used to determine if the OP_Affinity operation
+** can be omitted.  When in doubt return FALSE.  A false negative
+** is harmless.  A false positive, however, can result in the wrong
+** answer.
+*/
+int sqlite3ExprNeedsNoAffinityChange(const Expr *p, char aff){
+  u8 op;
+  if( aff==SQLITE_AFF_BLOB ) return 1;
+  while( p->op==TK_UPLUS || p->op==TK_UMINUS ){ p = p->pLeft; }
+  op = p->op;
+  if( op==TK_REGISTER ) op = p->op2;
+  switch( op ){
+    case TK_INTEGER: {
+      return aff==SQLITE_AFF_INTEGER || aff==SQLITE_AFF_NUMERIC;
+    }
+    case TK_FLOAT: {
+      return aff==SQLITE_AFF_REAL || aff==SQLITE_AFF_NUMERIC;
+    }
+    case TK_STRING: {
+      return aff==SQLITE_AFF_TEXT;
+    }
+    case TK_BLOB: {
+      return 1;
+    }
+    case TK_COLUMN: {
+      assert( p->iTable>=0 );  /* p cannot be part of a CHECK constraint */
+      return p->iColumn<0
+          && (aff==SQLITE_AFF_INTEGER || aff==SQLITE_AFF_NUMERIC);
+    }
+    default: {
+      return 0;
+    }
+  }
+}
+
+/*
+** Return TRUE if the given string is a row-id column name.
+*/
+int sqlite3IsRowid(const char *z){
+  if( sqlite3StrICmp(z, "_ROWID_")==0 ) return 1;
+  if( sqlite3StrICmp(z, "ROWID")==0 ) return 1;
+  if( sqlite3StrICmp(z, "OID")==0 ) return 1;
+  return 0;
+}
+
+/*
+** pX is the RHS of an IN operator.  If pX is a SELECT statement 
+** that can be simplified to a direct table access, then return
+** a pointer to the SELECT statement.  If pX is not a SELECT statement,
+** or if the SELECT statement needs to be manifested into a transient
+** table, then return NULL.
+*/
+#ifndef SQLITE_OMIT_SUBQUERY
+static Select *isCandidateForInOpt(Expr *pX){
+  Select *p;
+  SrcList *pSrc;
+  ExprList *pEList;
+  Table *pTab;
+  int i;
+  if( !ExprHasProperty(pX, EP_xIsSelect) ) return 0;  /* Not a subquery */
+  if( ExprHasProperty(pX, EP_VarSelect)  ) return 0;  /* Correlated subq */
+  p = pX->x.pSelect;
+  if( p->pPrior ) return 0;              /* Not a compound SELECT */
+  if( p->selFlags & (SF_Distinct|SF_Aggregate) ){
+    testcase( (p->selFlags & (SF_Distinct|SF_Aggregate))==SF_Distinct );
+    testcase( (p->selFlags & (SF_Distinct|SF_Aggregate))==SF_Aggregate );
+    return 0; /* No DISTINCT keyword and no aggregate functions */
+  }
+  assert( p->pGroupBy==0 );              /* Has no GROUP BY clause */
+  if( p->pLimit ) return 0;              /* Has no LIMIT clause */
+  assert( p->pOffset==0 );               /* No LIMIT means no OFFSET */
+  if( p->pWhere ) return 0;              /* Has no WHERE clause */
+  pSrc = p->pSrc;
+  assert( pSrc!=0 );
+  if( pSrc->nSrc!=1 ) return 0;          /* Single term in FROM clause */
+  if( pSrc->a[0].pSelect ) return 0;     /* FROM is not a subquery or view */
+  pTab = pSrc->a[0].pTab;
+  assert( pTab!=0 );
+  assert( pTab->pSelect==0 );            /* FROM clause is not a view */
+  if( IsVirtual(pTab) ) return 0;        /* FROM clause not a virtual table */
+  pEList = p->pEList;
+  assert( pEList!=0 );
+  /* All SELECT results must be columns. */
+  for(i=0; i<pEList->nExpr; i++){
+    Expr *pRes = pEList->a[i].pExpr;
+    if( pRes->op!=TK_COLUMN ) return 0;
+    assert( pRes->iTable==pSrc->a[0].iCursor );  /* Not a correlated subquery */
+  }
+  return p;
+}
+#endif /* SQLITE_OMIT_SUBQUERY */
+
+#ifndef SQLITE_OMIT_SUBQUERY
+/*
+** Generate code that checks the left-most column of index table iCur to see if
+** it contains any NULL entries.  Cause the register at regHasNull to be set
+** to a non-NULL value if iCur contains no NULLs.  Cause register regHasNull
+** to be set to NULL if iCur contains one or more NULL values.
+*/
+static void sqlite3SetHasNullFlag(Vdbe *v, int iCur, int regHasNull){
+  int addr1;
+  sqlite3VdbeAddOp2(v, OP_Integer, 0, regHasNull);
+  addr1 = sqlite3VdbeAddOp1(v, OP_Rewind, iCur); VdbeCoverage(v);
+  sqlite3VdbeAddOp3(v, OP_Column, iCur, 0, regHasNull);
+  sqlite3VdbeChangeP5(v, OPFLAG_TYPEOFARG);
+  VdbeComment((v, "first_entry_in(%d)", iCur));
+  sqlite3VdbeJumpHere(v, addr1);
+}
+#endif
+
+
+#ifndef SQLITE_OMIT_SUBQUERY
+/*
+** The argument is an IN operator with a list (not a subquery) on the 
+** right-hand side.  Return TRUE if that list is constant.
+*/
+static int sqlite3InRhsIsConstant(Expr *pIn){
+  Expr *pLHS;
+  int res;
+  assert( !ExprHasProperty(pIn, EP_xIsSelect) );
+  pLHS = pIn->pLeft;
+  pIn->pLeft = 0;
+  res = sqlite3ExprIsConstant(pIn);
+  pIn->pLeft = pLHS;
+  return res;
+}
+#endif
+
+/*
+** This function is used by the implementation of the IN (...) operator.
+** The pX parameter is the expression on the RHS of the IN operator, which
+** might be either a list of expressions or a subquery.
+**
+** The job of this routine is to find or create a b-tree object that can
+** be used either to test for membership in the RHS set or to iterate through
+** all members of the RHS set, skipping duplicates.
+**
+** A cursor is opened on the b-tree object that is the RHS of the IN operator
+** and pX->iTable is set to the index of that cursor.
+**
+** The returned value of this function indicates the b-tree type, as follows:
+**
+**   IN_INDEX_ROWID      - The cursor was opened on a database table.
+**   IN_INDEX_INDEX_ASC  - The cursor was opened on an ascending index.
+**   IN_INDEX_INDEX_DESC - The cursor was opened on a descending index.
+**   IN_INDEX_EPH        - The cursor was opened on a specially created and
+**                         populated epheremal table.
+**   IN_INDEX_NOOP       - No cursor was allocated.  The IN operator must be
+**                         implemented as a sequence of comparisons.
+**
+** An existing b-tree might be used if the RHS expression pX is a simple
+** subquery such as:
+**
+**     SELECT <column1>, <column2>... FROM <table>
+**
+** If the RHS of the IN operator is a list or a more complex subquery, then
+** an ephemeral table might need to be generated from the RHS and then
+** pX->iTable made to point to the ephemeral table instead of an
+** existing table.
+**
+** The inFlags parameter must contain exactly one of the bits
+** IN_INDEX_MEMBERSHIP or IN_INDEX_LOOP.  If inFlags contains
+** IN_INDEX_MEMBERSHIP, then the generated table will be used for a
+** fast membership test.  When the IN_INDEX_LOOP bit is set, the
+** IN index will be used to loop over all values of the RHS of the
+** IN operator.
+**
+** When IN_INDEX_LOOP is used (and the b-tree will be used to iterate
+** through the set members) then the b-tree must not contain duplicates.
+** An epheremal table must be used unless the selected columns are guaranteed
+** to be unique - either because it is an INTEGER PRIMARY KEY or due to
+** a UNIQUE constraint or index.
+**
+** When IN_INDEX_MEMBERSHIP is used (and the b-tree will be used 
+** for fast set membership tests) then an epheremal table must 
+** be used unless <columns> is a single INTEGER PRIMARY KEY column or an 
+** index can be found with the specified <columns> as its left-most.
+**
+** If the IN_INDEX_NOOP_OK and IN_INDEX_MEMBERSHIP are both set and
+** if the RHS of the IN operator is a list (not a subquery) then this
+** routine might decide that creating an ephemeral b-tree for membership
+** testing is too expensive and return IN_INDEX_NOOP.  In that case, the
+** calling routine should implement the IN operator using a sequence
+** of Eq or Ne comparison operations.
+**
+** When the b-tree is being used for membership tests, the calling function
+** might need to know whether or not the RHS side of the IN operator
+** contains a NULL.  If prRhsHasNull is not a NULL pointer and 
+** if there is any chance that the (...) might contain a NULL value at
+** runtime, then a register is allocated and the register number written
+** to *prRhsHasNull. If there is no chance that the (...) contains a
+** NULL value, then *prRhsHasNull is left unchanged.
+**
+** If a register is allocated and its location stored in *prRhsHasNull, then
+** the value in that register will be NULL if the b-tree contains one or more
+** NULL values, and it will be some non-NULL value if the b-tree contains no
+** NULL values.
+**
+** If the aiMap parameter is not NULL, it must point to an array containing
+** one element for each column returned by the SELECT statement on the RHS
+** of the IN(...) operator. The i'th entry of the array is populated with the
+** offset of the index column that matches the i'th column returned by the
+** SELECT. For example, if the expression and selected index are:
+**
+**   (?,?,?) IN (SELECT a, b, c FROM t1)
+**   CREATE INDEX i1 ON t1(b, c, a);
+**
+** then aiMap[] is populated with {2, 0, 1}.
+*/
+#ifndef SQLITE_OMIT_SUBQUERY
+int sqlite3FindInIndex(
+  Parse *pParse,             /* Parsing context */
+  Expr *pX,                  /* The right-hand side (RHS) of the IN operator */
+  u32 inFlags,               /* IN_INDEX_LOOP, _MEMBERSHIP, and/or _NOOP_OK */
+  int *prRhsHasNull,         /* Register holding NULL status.  See notes */
+  int *aiMap                 /* Mapping from Index fields to RHS fields */
+){
+  Select *p;                            /* SELECT to the right of IN operator */
+  int eType = 0;                        /* Type of RHS table. IN_INDEX_* */
+  int iTab = pParse->nTab++;            /* Cursor of the RHS table */
+  int mustBeUnique;                     /* True if RHS must be unique */
+  Vdbe *v = sqlite3GetVdbe(pParse);     /* Virtual machine being coded */
+
+  assert( pX->op==TK_IN );
+  mustBeUnique = (inFlags & IN_INDEX_LOOP)!=0;
+
+  /* If the RHS of this IN(...) operator is a SELECT, and if it matters 
+  ** whether or not the SELECT result contains NULL values, check whether
+  ** or not NULL is actually possible (it may not be, for example, due 
+  ** to NOT NULL constraints in the schema). If no NULL values are possible,
+  ** set prRhsHasNull to 0 before continuing.  */
+  if( prRhsHasNull && (pX->flags & EP_xIsSelect) ){
+    int i;
+    ExprList *pEList = pX->x.pSelect->pEList;
+    for(i=0; i<pEList->nExpr; i++){
+      if( sqlite3ExprCanBeNull(pEList->a[i].pExpr) ) break;
+    }
+    if( i==pEList->nExpr ){
+      prRhsHasNull = 0;
+    }
+  }
+
+  /* Check to see if an existing table or index can be used to
+  ** satisfy the query.  This is preferable to generating a new 
+  ** ephemeral table.  */
+  if( pParse->nErr==0 && (p = isCandidateForInOpt(pX))!=0 ){
+    sqlite3 *db = pParse->db;              /* Database connection */
+    Table *pTab;                           /* Table <table>. */
+    i16 iDb;                               /* Database idx for pTab */
+    ExprList *pEList = p->pEList;
+    int nExpr = pEList->nExpr;
+
+    assert( p->pEList!=0 );             /* Because of isCandidateForInOpt(p) */
+    assert( p->pEList->a[0].pExpr!=0 ); /* Because of isCandidateForInOpt(p) */
+    assert( p->pSrc!=0 );               /* Because of isCandidateForInOpt(p) */
+    pTab = p->pSrc->a[0].pTab;
+
+    /* Code an OP_Transaction and OP_TableLock for <table>. */
+    iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+    sqlite3CodeVerifySchema(pParse, iDb);
+    sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName);
+
+    assert(v);  /* sqlite3GetVdbe() has always been previously called */
+    if( nExpr==1 && pEList->a[0].pExpr->iColumn<0 ){
+      /* The "x IN (SELECT rowid FROM table)" case */
+      int iAddr = sqlite3VdbeAddOp0(v, OP_Once);
+      VdbeCoverage(v);
+
+      sqlite3OpenTable(pParse, iTab, iDb, pTab, OP_OpenRead);
+      eType = IN_INDEX_ROWID;
+
+      sqlite3VdbeJumpHere(v, iAddr);
+    }else{
+      Index *pIdx;                         /* Iterator variable */
+      int affinity_ok = 1;
+      int i;
+
+      /* Check that the affinity that will be used to perform each 
+      ** comparison is the same as the affinity of each column in table
+      ** on the RHS of the IN operator.  If it not, it is not possible to
+      ** use any index of the RHS table.  */
+      for(i=0; i<nExpr && affinity_ok; i++){
+        Expr *pLhs = sqlite3VectorFieldSubexpr(pX->pLeft, i);
+        int iCol = pEList->a[i].pExpr->iColumn;
+        char idxaff = sqlite3TableColumnAffinity(pTab,iCol); /* RHS table */
+        char cmpaff = sqlite3CompareAffinity(pLhs, idxaff);
+        testcase( cmpaff==SQLITE_AFF_BLOB );
+        testcase( cmpaff==SQLITE_AFF_TEXT );
+        switch( cmpaff ){
+          case SQLITE_AFF_BLOB:
+            break;
+          case SQLITE_AFF_TEXT:
+            /* sqlite3CompareAffinity() only returns TEXT if one side or the
+            ** other has no affinity and the other side is TEXT.  Hence,
+            ** the only way for cmpaff to be TEXT is for idxaff to be TEXT
+            ** and for the term on the LHS of the IN to have no affinity. */
+            assert( idxaff==SQLITE_AFF_TEXT );
+            break;
+          default:
+            affinity_ok = sqlite3IsNumericAffinity(idxaff);
+        }
+      }
+
+      if( affinity_ok ){
+        /* Search for an existing index that will work for this IN operator */
+        for(pIdx=pTab->pIndex; pIdx && eType==0; pIdx=pIdx->pNext){
+          Bitmask colUsed;      /* Columns of the index used */
+          Bitmask mCol;         /* Mask for the current column */
+          if( pIdx->nColumn<nExpr ) continue;
+          /* Maximum nColumn is BMS-2, not BMS-1, so that we can compute
+          ** BITMASK(nExpr) without overflowing */
+          testcase( pIdx->nColumn==BMS-2 );
+          testcase( pIdx->nColumn==BMS-1 );
+          if( pIdx->nColumn>=BMS-1 ) continue;
+          if( mustBeUnique ){
+            if( pIdx->nKeyCol>nExpr
+             ||(pIdx->nColumn>nExpr && !IsUniqueIndex(pIdx))
+            ){
+              continue;  /* This index is not unique over the IN RHS columns */
+            }
+          }
+  
+          colUsed = 0;   /* Columns of index used so far */
+          for(i=0; i<nExpr; i++){
+            Expr *pLhs = sqlite3VectorFieldSubexpr(pX->pLeft, i);
+            Expr *pRhs = pEList->a[i].pExpr;
+            CollSeq *pReq = sqlite3BinaryCompareCollSeq(pParse, pLhs, pRhs);
+            int j;
+  
+            assert( pReq!=0 || pRhs->iColumn==XN_ROWID || pParse->nErr );
+            for(j=0; j<nExpr; j++){
+              if( pIdx->aiColumn[j]!=pRhs->iColumn ) continue;
+              assert( pIdx->azColl[j] );
+              if( pReq!=0 && sqlite3StrICmp(pReq->zName, pIdx->azColl[j])!=0 ){
+                continue;
+              }
+              break;
+            }
+            if( j==nExpr ) break;
+            mCol = MASKBIT(j);
+            if( mCol & colUsed ) break; /* Each column used only once */
+            colUsed |= mCol;
+            if( aiMap ) aiMap[i] = j;
+          }
+  
+          assert( i==nExpr || colUsed!=(MASKBIT(nExpr)-1) );
+          if( colUsed==(MASKBIT(nExpr)-1) ){
+            /* If we reach this point, that means the index pIdx is usable */
+            int iAddr = sqlite3VdbeAddOp0(v, OP_Once); VdbeCoverage(v);
+#ifndef SQLITE_OMIT_EXPLAIN
+            sqlite3VdbeAddOp4(v, OP_Explain, 0, 0, 0,
+              sqlite3MPrintf(db, "USING INDEX %s FOR IN-OPERATOR",pIdx->zName),
+              P4_DYNAMIC);
+#endif
+            sqlite3VdbeAddOp3(v, OP_OpenRead, iTab, pIdx->tnum, iDb);
+            sqlite3VdbeSetP4KeyInfo(pParse, pIdx);
+            VdbeComment((v, "%s", pIdx->zName));
+            assert( IN_INDEX_INDEX_DESC == IN_INDEX_INDEX_ASC+1 );
+            eType = IN_INDEX_INDEX_ASC + pIdx->aSortOrder[0];
+  
+            if( prRhsHasNull ){
+#ifdef SQLITE_ENABLE_COLUMN_USED_MASK
+              i64 mask = (1<<nExpr)-1;
+              sqlite3VdbeAddOp4Dup8(v, OP_ColumnsUsed, 
+                  iTab, 0, 0, (u8*)&mask, P4_INT64);
+#endif
+              *prRhsHasNull = ++pParse->nMem;
+              if( nExpr==1 ){
+                sqlite3SetHasNullFlag(v, iTab, *prRhsHasNull);
+              }
+            }
+            sqlite3VdbeJumpHere(v, iAddr);
+          }
+        } /* End loop over indexes */
+      } /* End if( affinity_ok ) */
+    } /* End if not an rowid index */
+  } /* End attempt to optimize using an index */
+
+  /* If no preexisting index is available for the IN clause
+  ** and IN_INDEX_NOOP is an allowed reply
+  ** and the RHS of the IN operator is a list, not a subquery
+  ** and the RHS is not constant or has two or fewer terms,
+  ** then it is not worth creating an ephemeral table to evaluate
+  ** the IN operator so return IN_INDEX_NOOP.
+  */
+  if( eType==0
+   && (inFlags & IN_INDEX_NOOP_OK)
+   && !ExprHasProperty(pX, EP_xIsSelect)
+   && (!sqlite3InRhsIsConstant(pX) || pX->x.pList->nExpr<=2)
+  ){
+    eType = IN_INDEX_NOOP;
+  }
+
+  if( eType==0 ){
+    /* Could not find an existing table or index to use as the RHS b-tree.
+    ** We will have to generate an ephemeral table to do the job.
+    */
+    u32 savedNQueryLoop = pParse->nQueryLoop;
+    int rMayHaveNull = 0;
+    eType = IN_INDEX_EPH;
+    if( inFlags & IN_INDEX_LOOP ){
+      pParse->nQueryLoop = 0;
+      if( pX->pLeft->iColumn<0 && !ExprHasProperty(pX, EP_xIsSelect) ){
+        eType = IN_INDEX_ROWID;
+      }
+    }else if( prRhsHasNull ){
+      *prRhsHasNull = rMayHaveNull = ++pParse->nMem;
+    }
+    sqlite3CodeSubselect(pParse, pX, rMayHaveNull, eType==IN_INDEX_ROWID);
+    pParse->nQueryLoop = savedNQueryLoop;
+  }else{
+    pX->iTable = iTab;
+  }
+
+  if( aiMap && eType!=IN_INDEX_INDEX_ASC && eType!=IN_INDEX_INDEX_DESC ){
+    int i, n;
+    n = sqlite3ExprVectorSize(pX->pLeft);
+    for(i=0; i<n; i++) aiMap[i] = i;
+  }
+  return eType;
+}
+#endif
+
+#ifndef SQLITE_OMIT_SUBQUERY
+/*
+** Argument pExpr is an (?, ?...) IN(...) expression. This 
+** function allocates and returns a nul-terminated string containing 
+** the affinities to be used for each column of the comparison.
+**
+** It is the responsibility of the caller to ensure that the returned
+** string is eventually freed using sqlite3DbFree().
+*/
+static char *exprINAffinity(Parse *pParse, Expr *pExpr){
+  Expr *pLeft = pExpr->pLeft;
+  int nVal = sqlite3ExprVectorSize(pLeft);
+  Select *pSelect = (pExpr->flags & EP_xIsSelect) ? pExpr->x.pSelect : 0;
+  char *zRet;
+
+  assert( pExpr->op==TK_IN );
+  zRet = sqlite3DbMallocZero(pParse->db, nVal+1);
+  if( zRet ){
+    int i;
+    for(i=0; i<nVal; i++){
+      Expr *pA = sqlite3VectorFieldSubexpr(pLeft, i);
+      char a = sqlite3ExprAffinity(pA);
+      if( pSelect ){
+        zRet[i] = sqlite3CompareAffinity(pSelect->pEList->a[i].pExpr, a);
+      }else{
+        zRet[i] = a;
+      }
+    }
+    zRet[nVal] = '\0';
+  }
+  return zRet;
+}
+#endif
+
+#ifndef SQLITE_OMIT_SUBQUERY
+/*
+** Load the Parse object passed as the first argument with an error 
+** message of the form:
+**
+**   "sub-select returns N columns - expected M"
+*/   
+void sqlite3SubselectError(Parse *pParse, int nActual, int nExpect){
+  const char *zFmt = "sub-select returns %d columns - expected %d";
+  sqlite3ErrorMsg(pParse, zFmt, nActual, nExpect);
+}
+#endif
+
+/*
+** Expression pExpr is a vector that has been used in a context where
+** it is not permitted. If pExpr is a sub-select vector, this routine 
+** loads the Parse object with a message of the form:
+**
+**   "sub-select returns N columns - expected 1"
+**
+** Or, if it is a regular scalar vector:
+**
+**   "row value misused"
+*/   
+void sqlite3VectorErrorMsg(Parse *pParse, Expr *pExpr){
+#ifndef SQLITE_OMIT_SUBQUERY
+  if( pExpr->flags & EP_xIsSelect ){
+    sqlite3SubselectError(pParse, pExpr->x.pSelect->pEList->nExpr, 1);
+  }else
+#endif
+  {
+    sqlite3ErrorMsg(pParse, "row value misused");
+  }
+}
+
+/*
+** Generate code for scalar subqueries used as a subquery expression, EXISTS,
+** or IN operators.  Examples:
+**
+**     (SELECT a FROM b)          -- subquery
+**     EXISTS (SELECT a FROM b)   -- EXISTS subquery
+**     x IN (4,5,11)              -- IN operator with list on right-hand side
+**     x IN (SELECT a FROM b)     -- IN operator with subquery on the right
+**
+** The pExpr parameter describes the expression that contains the IN
+** operator or subquery.
+**
+** If parameter isRowid is non-zero, then expression pExpr is guaranteed
+** to be of the form "<rowid> IN (?, ?, ?)", where <rowid> is a reference
+** to some integer key column of a table B-Tree. In this case, use an
+** intkey B-Tree to store the set of IN(...) values instead of the usual
+** (slower) variable length keys B-Tree.
+**
+** If rMayHaveNull is non-zero, that means that the operation is an IN
+** (not a SELECT or EXISTS) and that the RHS might contains NULLs.
+** All this routine does is initialize the register given by rMayHaveNull
+** to NULL.  Calling routines will take care of changing this register
+** value to non-NULL if the RHS is NULL-free.
+**
+** For a SELECT or EXISTS operator, return the register that holds the
+** result.  For a multi-column SELECT, the result is stored in a contiguous
+** array of registers and the return value is the register of the left-most
+** result column.  Return 0 for IN operators or if an error occurs.
+*/
+#ifndef SQLITE_OMIT_SUBQUERY
+int sqlite3CodeSubselect(
+  Parse *pParse,          /* Parsing context */
+  Expr *pExpr,            /* The IN, SELECT, or EXISTS operator */
+  int rHasNullFlag,       /* Register that records whether NULLs exist in RHS */
+  int isRowid             /* If true, LHS of IN operator is a rowid */
+){
+  int jmpIfDynamic = -1;                      /* One-time test address */
+  int rReg = 0;                           /* Register storing resulting */
+  Vdbe *v = sqlite3GetVdbe(pParse);
+  if( NEVER(v==0) ) return 0;
+  sqlite3ExprCachePush(pParse);
+
+  /* The evaluation of the IN/EXISTS/SELECT must be repeated every time it
+  ** is encountered if any of the following is true:
+  **
+  **    *  The right-hand side is a correlated subquery
+  **    *  The right-hand side is an expression list containing variables
+  **    *  We are inside a trigger
+  **
+  ** If all of the above are false, then we can run this code just once
+  ** save the results, and reuse the same result on subsequent invocations.
+  */
+  if( !ExprHasProperty(pExpr, EP_VarSelect) ){
+    jmpIfDynamic = sqlite3VdbeAddOp0(v, OP_Once); VdbeCoverage(v);
+  }
+
+#ifndef SQLITE_OMIT_EXPLAIN
+  if( pParse->explain==2 ){
+    char *zMsg = sqlite3MPrintf(pParse->db, "EXECUTE %s%s SUBQUERY %d",
+        jmpIfDynamic>=0?"":"CORRELATED ",
+        pExpr->op==TK_IN?"LIST":"SCALAR",
+        pParse->iNextSelectId
+    );
+    sqlite3VdbeAddOp4(v, OP_Explain, pParse->iSelectId, 0, 0, zMsg, P4_DYNAMIC);
+  }
+#endif
+
+  switch( pExpr->op ){
+    case TK_IN: {
+      int addr;                   /* Address of OP_OpenEphemeral instruction */
+      Expr *pLeft = pExpr->pLeft; /* the LHS of the IN operator */
+      KeyInfo *pKeyInfo = 0;      /* Key information */
+      int nVal;                   /* Size of vector pLeft */
+      
+      nVal = sqlite3ExprVectorSize(pLeft);
+      assert( !isRowid || nVal==1 );
+
+      /* Whether this is an 'x IN(SELECT...)' or an 'x IN(<exprlist>)'
+      ** expression it is handled the same way.  An ephemeral table is 
+      ** filled with index keys representing the results from the 
+      ** SELECT or the <exprlist>.
+      **
+      ** If the 'x' expression is a column value, or the SELECT...
+      ** statement returns a column value, then the affinity of that
+      ** column is used to build the index keys. If both 'x' and the
+      ** SELECT... statement are columns, then numeric affinity is used
+      ** if either column has NUMERIC or INTEGER affinity. If neither
+      ** 'x' nor the SELECT... statement are columns, then numeric affinity
+      ** is used.
+      */
+      pExpr->iTable = pParse->nTab++;
+      addr = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, 
+          pExpr->iTable, (isRowid?0:nVal));
+      pKeyInfo = isRowid ? 0 : sqlite3KeyInfoAlloc(pParse->db, nVal, 1);
+
+      if( ExprHasProperty(pExpr, EP_xIsSelect) ){
+        /* Case 1:     expr IN (SELECT ...)
+        **
+        ** Generate code to write the results of the select into the temporary
+        ** table allocated and opened above.
+        */
+        Select *pSelect = pExpr->x.pSelect;
+        ExprList *pEList = pSelect->pEList;
+
+        assert( !isRowid );
+        /* If the LHS and RHS of the IN operator do not match, that
+        ** error will have been caught long before we reach this point. */
+        if( ALWAYS(pEList->nExpr==nVal) ){
+          SelectDest dest;
+          int i;
+          sqlite3SelectDestInit(&dest, SRT_Set, pExpr->iTable);
+          dest.zAffSdst = exprINAffinity(pParse, pExpr);
+          assert( (pExpr->iTable&0x0000FFFF)==pExpr->iTable );
+          pSelect->iLimit = 0;
+          testcase( pSelect->selFlags & SF_Distinct );
+          testcase( pKeyInfo==0 ); /* Caused by OOM in sqlite3KeyInfoAlloc() */
+          if( sqlite3Select(pParse, pSelect, &dest) ){
+            sqlite3DbFree(pParse->db, dest.zAffSdst);
+            sqlite3KeyInfoUnref(pKeyInfo);
+            return 0;
+          }
+          sqlite3DbFree(pParse->db, dest.zAffSdst);
+          assert( pKeyInfo!=0 ); /* OOM will cause exit after sqlite3Select() */
+          assert( pEList!=0 );
+          assert( pEList->nExpr>0 );
+          assert( sqlite3KeyInfoIsWriteable(pKeyInfo) );
+          for(i=0; i<nVal; i++){
+            Expr *p = sqlite3VectorFieldSubexpr(pLeft, i);
+            pKeyInfo->aColl[i] = sqlite3BinaryCompareCollSeq(
+                pParse, p, pEList->a[i].pExpr
+            );
+          }
+        }
+      }else if( ALWAYS(pExpr->x.pList!=0) ){
+        /* Case 2:     expr IN (exprlist)
+        **
+        ** For each expression, build an index key from the evaluation and
+        ** store it in the temporary table. If <expr> is a column, then use
+        ** that columns affinity when building index keys. If <expr> is not
+        ** a column, use numeric affinity.
+        */
+        char affinity;            /* Affinity of the LHS of the IN */
+        int i;
+        ExprList *pList = pExpr->x.pList;
+        struct ExprList_item *pItem;
+        int r1, r2, r3;
+
+        affinity = sqlite3ExprAffinity(pLeft);
+        if( !affinity ){
+          affinity = SQLITE_AFF_BLOB;
+        }
+        if( pKeyInfo ){
+          assert( sqlite3KeyInfoIsWriteable(pKeyInfo) );
+          pKeyInfo->aColl[0] = sqlite3ExprCollSeq(pParse, pExpr->pLeft);
+        }
+
+        /* Loop through each expression in <exprlist>. */
+        r1 = sqlite3GetTempReg(pParse);
+        r2 = sqlite3GetTempReg(pParse);
+        if( isRowid ) sqlite3VdbeAddOp2(v, OP_Null, 0, r2);
+        for(i=pList->nExpr, pItem=pList->a; i>0; i--, pItem++){
+          Expr *pE2 = pItem->pExpr;
+          int iValToIns;
+
+          /* If the expression is not constant then we will need to
+          ** disable the test that was generated above that makes sure
+          ** this code only executes once.  Because for a non-constant
+          ** expression we need to rerun this code each time.
+          */
+          if( jmpIfDynamic>=0 && !sqlite3ExprIsConstant(pE2) ){
+            sqlite3VdbeChangeToNoop(v, jmpIfDynamic);
+            jmpIfDynamic = -1;
+          }
+
+          /* Evaluate the expression and insert it into the temp table */
+          if( isRowid && sqlite3ExprIsInteger(pE2, &iValToIns) ){
+            sqlite3VdbeAddOp3(v, OP_InsertInt, pExpr->iTable, r2, iValToIns);
+          }else{
+            r3 = sqlite3ExprCodeTarget(pParse, pE2, r1);
+            if( isRowid ){
+              sqlite3VdbeAddOp2(v, OP_MustBeInt, r3,
+                                sqlite3VdbeCurrentAddr(v)+2);
+              VdbeCoverage(v);
+              sqlite3VdbeAddOp3(v, OP_Insert, pExpr->iTable, r2, r3);
+            }else{
+              sqlite3VdbeAddOp4(v, OP_MakeRecord, r3, 1, r2, &affinity, 1);
+              sqlite3ExprCacheAffinityChange(pParse, r3, 1);
+              sqlite3VdbeAddOp4Int(v, OP_IdxInsert, pExpr->iTable, r2, r3, 1);
+            }
+          }
+        }
+        sqlite3ReleaseTempReg(pParse, r1);
+        sqlite3ReleaseTempReg(pParse, r2);
+      }
+      if( pKeyInfo ){
+        sqlite3VdbeChangeP4(v, addr, (void *)pKeyInfo, P4_KEYINFO);
+      }
+      break;
+    }
+
+    case TK_EXISTS:
+    case TK_SELECT:
+    default: {
+      /* Case 3:    (SELECT ... FROM ...)
+      **     or:    EXISTS(SELECT ... FROM ...)
+      **
+      ** For a SELECT, generate code to put the values for all columns of
+      ** the first row into an array of registers and return the index of
+      ** the first register.
+      **
+      ** If this is an EXISTS, write an integer 0 (not exists) or 1 (exists)
+      ** into a register and return that register number.
+      **
+      ** In both cases, the query is augmented with "LIMIT 1".  Any 
+      ** preexisting limit is discarded in place of the new LIMIT 1.
+      */
+      Select *pSel;                         /* SELECT statement to encode */
+      SelectDest dest;                      /* How to deal with SELECT result */
+      int nReg;                             /* Registers to allocate */
+
+      testcase( pExpr->op==TK_EXISTS );
+      testcase( pExpr->op==TK_SELECT );
+      assert( pExpr->op==TK_EXISTS || pExpr->op==TK_SELECT );
+      assert( ExprHasProperty(pExpr, EP_xIsSelect) );
+
+      pSel = pExpr->x.pSelect;
+      nReg = pExpr->op==TK_SELECT ? pSel->pEList->nExpr : 1;
+      sqlite3SelectDestInit(&dest, 0, pParse->nMem+1);
+      pParse->nMem += nReg;
+      if( pExpr->op==TK_SELECT ){
+        dest.eDest = SRT_Mem;
+        dest.iSdst = dest.iSDParm;
+        dest.nSdst = nReg;
+        sqlite3VdbeAddOp3(v, OP_Null, 0, dest.iSDParm, dest.iSDParm+nReg-1);
+        VdbeComment((v, "Init subquery result"));
+      }else{
+        dest.eDest = SRT_Exists;
+        sqlite3VdbeAddOp2(v, OP_Integer, 0, dest.iSDParm);
+        VdbeComment((v, "Init EXISTS result"));
+      }
+      sqlite3ExprDelete(pParse->db, pSel->pLimit);
+      pSel->pLimit = sqlite3ExprAlloc(pParse->db, TK_INTEGER,
+                                  &sqlite3IntTokens[1], 0);
+      pSel->iLimit = 0;
+      pSel->selFlags &= ~SF_MultiValue;
+      if( sqlite3Select(pParse, pSel, &dest) ){
+        return 0;
+      }
+      rReg = dest.iSDParm;
+      ExprSetVVAProperty(pExpr, EP_NoReduce);
+      break;
+    }
+  }
+
+  if( rHasNullFlag ){
+    sqlite3SetHasNullFlag(v, pExpr->iTable, rHasNullFlag);
+  }
+
+  if( jmpIfDynamic>=0 ){
+    sqlite3VdbeJumpHere(v, jmpIfDynamic);
+  }
+  sqlite3ExprCachePop(pParse);
+
+  return rReg;
+}
+#endif /* SQLITE_OMIT_SUBQUERY */
+
+#ifndef SQLITE_OMIT_SUBQUERY
+/*
+** Expr pIn is an IN(...) expression. This function checks that the 
+** sub-select on the RHS of the IN() operator has the same number of 
+** columns as the vector on the LHS. Or, if the RHS of the IN() is not 
+** a sub-query, that the LHS is a vector of size 1.
+*/
+int sqlite3ExprCheckIN(Parse *pParse, Expr *pIn){
+  int nVector = sqlite3ExprVectorSize(pIn->pLeft);
+  if( (pIn->flags & EP_xIsSelect) ){
+    if( nVector!=pIn->x.pSelect->pEList->nExpr ){
+      sqlite3SubselectError(pParse, pIn->x.pSelect->pEList->nExpr, nVector);
+      return 1;
+    }
+  }else if( nVector!=1 ){
+    sqlite3VectorErrorMsg(pParse, pIn->pLeft);
+    return 1;
+  }
+  return 0;
+}
+#endif
+
+#ifndef SQLITE_OMIT_SUBQUERY
+/*
+** Generate code for an IN expression.
+**
+**      x IN (SELECT ...)
+**      x IN (value, value, ...)
+**
+** The left-hand side (LHS) is a scalar or vector expression.  The 
+** right-hand side (RHS) is an array of zero or more scalar values, or a
+** subquery.  If the RHS is a subquery, the number of result columns must
+** match the number of columns in the vector on the LHS.  If the RHS is
+** a list of values, the LHS must be a scalar. 
+**
+** The IN operator is true if the LHS value is contained within the RHS.
+** The result is false if the LHS is definitely not in the RHS.  The 
+** result is NULL if the presence of the LHS in the RHS cannot be 
+** determined due to NULLs.
+**
+** This routine generates code that jumps to destIfFalse if the LHS is not 
+** contained within the RHS.  If due to NULLs we cannot determine if the LHS
+** is contained in the RHS then jump to destIfNull.  If the LHS is contained
+** within the RHS then fall through.
+**
+** See the separate in-operator.md documentation file in the canonical
+** SQLite source tree for additional information.
+*/
+static void sqlite3ExprCodeIN(
+  Parse *pParse,        /* Parsing and code generating context */
+  Expr *pExpr,          /* The IN expression */
+  int destIfFalse,      /* Jump here if LHS is not contained in the RHS */
+  int destIfNull        /* Jump here if the results are unknown due to NULLs */
+){
+  int rRhsHasNull = 0;  /* Register that is true if RHS contains NULL values */
+  int eType;            /* Type of the RHS */
+  int rLhs;             /* Register(s) holding the LHS values */
+  int rLhsOrig;         /* LHS values prior to reordering by aiMap[] */
+  Vdbe *v;              /* Statement under construction */
+  int *aiMap = 0;       /* Map from vector field to index column */
+  char *zAff = 0;       /* Affinity string for comparisons */
+  int nVector;          /* Size of vectors for this IN operator */
+  int iDummy;           /* Dummy parameter to exprCodeVector() */
+  Expr *pLeft;          /* The LHS of the IN operator */
+  int i;                /* loop counter */
+  int destStep2;        /* Where to jump when NULLs seen in step 2 */
+  int destStep6 = 0;    /* Start of code for Step 6 */
+  int addrTruthOp;      /* Address of opcode that determines the IN is true */
+  int destNotNull;      /* Jump here if a comparison is not true in step 6 */
+  int addrTop;          /* Top of the step-6 loop */ 
+
+  pLeft = pExpr->pLeft;
+  if( sqlite3ExprCheckIN(pParse, pExpr) ) return;
+  zAff = exprINAffinity(pParse, pExpr);
+  nVector = sqlite3ExprVectorSize(pExpr->pLeft);
+  aiMap = (int*)sqlite3DbMallocZero(
+      pParse->db, nVector*(sizeof(int) + sizeof(char)) + 1
+  );
+  if( pParse->db->mallocFailed ) goto sqlite3ExprCodeIN_oom_error;
+
+  /* Attempt to compute the RHS. After this step, if anything other than
+  ** IN_INDEX_NOOP is returned, the table opened ith cursor pExpr->iTable 
+  ** contains the values that make up the RHS. If IN_INDEX_NOOP is returned,
+  ** the RHS has not yet been coded.  */
+  v = pParse->pVdbe;
+  assert( v!=0 );       /* OOM detected prior to this routine */
+  VdbeNoopComment((v, "begin IN expr"));
+  eType = sqlite3FindInIndex(pParse, pExpr,
+                             IN_INDEX_MEMBERSHIP | IN_INDEX_NOOP_OK,
+                             destIfFalse==destIfNull ? 0 : &rRhsHasNull, aiMap);
+
+  assert( pParse->nErr || nVector==1 || eType==IN_INDEX_EPH
+       || eType==IN_INDEX_INDEX_ASC || eType==IN_INDEX_INDEX_DESC 
+  );
+#ifdef SQLITE_DEBUG
+  /* Confirm that aiMap[] contains nVector integer values between 0 and
+  ** nVector-1. */
+  for(i=0; i<nVector; i++){
+    int j, cnt;
+    for(cnt=j=0; j<nVector; j++) if( aiMap[j]==i ) cnt++;
+    assert( cnt==1 );
+  }
+#endif
+
+  /* Code the LHS, the <expr> from "<expr> IN (...)". If the LHS is a 
+  ** vector, then it is stored in an array of nVector registers starting 
+  ** at r1.
+  **
+  ** sqlite3FindInIndex() might have reordered the fields of the LHS vector
+  ** so that the fields are in the same order as an existing index.   The
+  ** aiMap[] array contains a mapping from the original LHS field order to
+  ** the field order that matches the RHS index.
+  */
+  sqlite3ExprCachePush(pParse);
+  rLhsOrig = exprCodeVector(pParse, pLeft, &iDummy);
+  for(i=0; i<nVector && aiMap[i]==i; i++){} /* Are LHS fields reordered? */
+  if( i==nVector ){
+    /* LHS fields are not reordered */
+    rLhs = rLhsOrig;
+  }else{
+    /* Need to reorder the LHS fields according to aiMap */
+    rLhs = sqlite3GetTempRange(pParse, nVector);
+    for(i=0; i<nVector; i++){
+      sqlite3VdbeAddOp3(v, OP_Copy, rLhsOrig+i, rLhs+aiMap[i], 0);
+    }
+  }
+
+  /* If sqlite3FindInIndex() did not find or create an index that is
+  ** suitable for evaluating the IN operator, then evaluate using a
+  ** sequence of comparisons.
+  **
+  ** This is step (1) in the in-operator.md optimized algorithm.
+  */
+  if( eType==IN_INDEX_NOOP ){
+    ExprList *pList = pExpr->x.pList;
+    CollSeq *pColl = sqlite3ExprCollSeq(pParse, pExpr->pLeft);
+    int labelOk = sqlite3VdbeMakeLabel(v);
+    int r2, regToFree;
+    int regCkNull = 0;
+    int ii;
+    assert( !ExprHasProperty(pExpr, EP_xIsSelect) );
+    if( destIfNull!=destIfFalse ){
+      regCkNull = sqlite3GetTempReg(pParse);
+      sqlite3VdbeAddOp3(v, OP_BitAnd, rLhs, rLhs, regCkNull);
+    }
+    for(ii=0; ii<pList->nExpr; ii++){
+      r2 = sqlite3ExprCodeTemp(pParse, pList->a[ii].pExpr, &regToFree);
+      if( regCkNull && sqlite3ExprCanBeNull(pList->a[ii].pExpr) ){
+        sqlite3VdbeAddOp3(v, OP_BitAnd, regCkNull, r2, regCkNull);
+      }
+      if( ii<pList->nExpr-1 || destIfNull!=destIfFalse ){
+        sqlite3VdbeAddOp4(v, OP_Eq, rLhs, labelOk, r2,
+                          (void*)pColl, P4_COLLSEQ);
+        VdbeCoverageIf(v, ii<pList->nExpr-1);
+        VdbeCoverageIf(v, ii==pList->nExpr-1);
+        sqlite3VdbeChangeP5(v, zAff[0]);
+      }else{
+        assert( destIfNull==destIfFalse );
+        sqlite3VdbeAddOp4(v, OP_Ne, rLhs, destIfFalse, r2,
+                          (void*)pColl, P4_COLLSEQ); VdbeCoverage(v);
+        sqlite3VdbeChangeP5(v, zAff[0] | SQLITE_JUMPIFNULL);
+      }
+      sqlite3ReleaseTempReg(pParse, regToFree);
+    }
+    if( regCkNull ){
+      sqlite3VdbeAddOp2(v, OP_IsNull, regCkNull, destIfNull); VdbeCoverage(v);
+      sqlite3VdbeGoto(v, destIfFalse);
+    }
+    sqlite3VdbeResolveLabel(v, labelOk);
+    sqlite3ReleaseTempReg(pParse, regCkNull);
+    goto sqlite3ExprCodeIN_finished;
+  }
+
+  /* Step 2: Check to see if the LHS contains any NULL columns.  If the
+  ** LHS does contain NULLs then the result must be either FALSE or NULL.
+  ** We will then skip the binary search of the RHS.
+  */
+  if( destIfNull==destIfFalse ){
+    destStep2 = destIfFalse;
+  }else{
+    destStep2 = destStep6 = sqlite3VdbeMakeLabel(v);
+  }
+  for(i=0; i<nVector; i++){
+    Expr *p = sqlite3VectorFieldSubexpr(pExpr->pLeft, i);
+    if( sqlite3ExprCanBeNull(p) ){
+      sqlite3VdbeAddOp2(v, OP_IsNull, rLhs+i, destStep2);
+      VdbeCoverage(v);
+    }
+  }
+
+  /* Step 3.  The LHS is now known to be non-NULL.  Do the binary search
+  ** of the RHS using the LHS as a probe.  If found, the result is
+  ** true.
+  */
+  if( eType==IN_INDEX_ROWID ){
+    /* In this case, the RHS is the ROWID of table b-tree and so we also
+    ** know that the RHS is non-NULL.  Hence, we combine steps 3 and 4
+    ** into a single opcode. */
+    sqlite3VdbeAddOp3(v, OP_SeekRowid, pExpr->iTable, destIfFalse, rLhs);
+    VdbeCoverage(v);
+    addrTruthOp = sqlite3VdbeAddOp0(v, OP_Goto);  /* Return True */
+  }else{
+    sqlite3VdbeAddOp4(v, OP_Affinity, rLhs, nVector, 0, zAff, nVector);
+    if( destIfFalse==destIfNull ){
+      /* Combine Step 3 and Step 5 into a single opcode */
+      sqlite3VdbeAddOp4Int(v, OP_NotFound, pExpr->iTable, destIfFalse,
+                           rLhs, nVector); VdbeCoverage(v);
+      goto sqlite3ExprCodeIN_finished;
+    }
+    /* Ordinary Step 3, for the case where FALSE and NULL are distinct */
+    addrTruthOp = sqlite3VdbeAddOp4Int(v, OP_Found, pExpr->iTable, 0,
+                                      rLhs, nVector); VdbeCoverage(v);
+  }
+
+  /* Step 4.  If the RHS is known to be non-NULL and we did not find
+  ** an match on the search above, then the result must be FALSE.
+  */
+  if( rRhsHasNull && nVector==1 ){
+    sqlite3VdbeAddOp2(v, OP_NotNull, rRhsHasNull, destIfFalse);
+    VdbeCoverage(v);
+  }
+
+  /* Step 5.  If we do not care about the difference between NULL and
+  ** FALSE, then just return false. 
+  */
+  if( destIfFalse==destIfNull ) sqlite3VdbeGoto(v, destIfFalse);
+
+  /* Step 6: Loop through rows of the RHS.  Compare each row to the LHS.
+  ** If any comparison is NULL, then the result is NULL.  If all
+  ** comparisons are FALSE then the final result is FALSE.
+  **
+  ** For a scalar LHS, it is sufficient to check just the first row
+  ** of the RHS.
+  */
+  if( destStep6 ) sqlite3VdbeResolveLabel(v, destStep6);
+  addrTop = sqlite3VdbeAddOp2(v, OP_Rewind, pExpr->iTable, destIfFalse);
+  VdbeCoverage(v);
+  if( nVector>1 ){
+    destNotNull = sqlite3VdbeMakeLabel(v);
+  }else{
+    /* For nVector==1, combine steps 6 and 7 by immediately returning
+    ** FALSE if the first comparison is not NULL */
+    destNotNull = destIfFalse;
+  }
+  for(i=0; i<nVector; i++){
+    Expr *p;
+    CollSeq *pColl;
+    int r3 = sqlite3GetTempReg(pParse);
+    p = sqlite3VectorFieldSubexpr(pLeft, i);
+    pColl = sqlite3ExprCollSeq(pParse, p);
+    sqlite3VdbeAddOp3(v, OP_Column, pExpr->iTable, i, r3);
+    sqlite3VdbeAddOp4(v, OP_Ne, rLhs+i, destNotNull, r3,
+                      (void*)pColl, P4_COLLSEQ);
+    VdbeCoverage(v);
+    sqlite3ReleaseTempReg(pParse, r3);
+  }
+  sqlite3VdbeAddOp2(v, OP_Goto, 0, destIfNull);
+  if( nVector>1 ){
+    sqlite3VdbeResolveLabel(v, destNotNull);
+    sqlite3VdbeAddOp2(v, OP_Next, pExpr->iTable, addrTop+1);
+    VdbeCoverage(v);
+
+    /* Step 7:  If we reach this point, we know that the result must
+    ** be false. */
+    sqlite3VdbeAddOp2(v, OP_Goto, 0, destIfFalse);
+  }
+
+  /* Jumps here in order to return true. */
+  sqlite3VdbeJumpHere(v, addrTruthOp);
+
+sqlite3ExprCodeIN_finished:
+  if( rLhs!=rLhsOrig ) sqlite3ReleaseTempReg(pParse, rLhs);
+  sqlite3ExprCachePop(pParse);
+  VdbeComment((v, "end IN expr"));
+sqlite3ExprCodeIN_oom_error:
+  sqlite3DbFree(pParse->db, aiMap);
+  sqlite3DbFree(pParse->db, zAff);
+}
+#endif /* SQLITE_OMIT_SUBQUERY */
+
+#ifndef SQLITE_OMIT_FLOATING_POINT
+/*
+** Generate an instruction that will put the floating point
+** value described by z[0..n-1] into register iMem.
+**
+** The z[] string will probably not be zero-terminated.  But the 
+** z[n] character is guaranteed to be something that does not look
+** like the continuation of the number.
+*/
+static void codeReal(Vdbe *v, const char *z, int negateFlag, int iMem){
+  if( ALWAYS(z!=0) ){
+    double value;
+    sqlite3AtoF(z, &value, sqlite3Strlen30(z), SQLITE_UTF8);
+    assert( !sqlite3IsNaN(value) ); /* The new AtoF never returns NaN */
+    if( negateFlag ) value = -value;
+    sqlite3VdbeAddOp4Dup8(v, OP_Real, 0, iMem, 0, (u8*)&value, P4_REAL);
+  }
+}
+#endif
+
+
+/*
+** Generate an instruction that will put the integer describe by
+** text z[0..n-1] into register iMem.
+**
+** Expr.u.zToken is always UTF8 and zero-terminated.
+*/
+static void codeInteger(Parse *pParse, Expr *pExpr, int negFlag, int iMem){
+  Vdbe *v = pParse->pVdbe;
+  if( pExpr->flags & EP_IntValue ){
+    int i = pExpr->u.iValue;
+    assert( i>=0 );
+    if( negFlag ) i = -i;
+    sqlite3VdbeAddOp2(v, OP_Integer, i, iMem);
+  }else{
+    int c;
+    i64 value;
+    const char *z = pExpr->u.zToken;
+    assert( z!=0 );
+    c = sqlite3DecOrHexToI64(z, &value);
+    if( c==1 || (c==2 && !negFlag) || (negFlag && value==SMALLEST_INT64)){
+#ifdef SQLITE_OMIT_FLOATING_POINT
+      sqlite3ErrorMsg(pParse, "oversized integer: %s%s", negFlag ? "-" : "", z);
+#else
+#ifndef SQLITE_OMIT_HEX_INTEGER
+      if( sqlite3_strnicmp(z,"0x",2)==0 ){
+        sqlite3ErrorMsg(pParse, "hex literal too big: %s%s", negFlag?"-":"",z);
+      }else
+#endif
+      {
+        codeReal(v, z, negFlag, iMem);
+      }
+#endif
+    }else{
+      if( negFlag ){ value = c==2 ? SMALLEST_INT64 : -value; }
+      sqlite3VdbeAddOp4Dup8(v, OP_Int64, 0, iMem, 0, (u8*)&value, P4_INT64);
+    }
+  }
+}
+
+/*
+** Erase column-cache entry number i
+*/
+static void cacheEntryClear(Parse *pParse, int i){
+  if( pParse->aColCache[i].tempReg ){
+    if( pParse->nTempReg<ArraySize(pParse->aTempReg) ){
+      pParse->aTempReg[pParse->nTempReg++] = pParse->aColCache[i].iReg;
+    }
+  }
+  pParse->nColCache--;
+  if( i<pParse->nColCache ){
+    pParse->aColCache[i] = pParse->aColCache[pParse->nColCache];
+  }
+}
+
+
+/*
+** Record in the column cache that a particular column from a
+** particular table is stored in a particular register.
+*/
+void sqlite3ExprCacheStore(Parse *pParse, int iTab, int iCol, int iReg){
+  int i;
+  int minLru;
+  int idxLru;
+  struct yColCache *p;
+
+  /* Unless an error has occurred, register numbers are always positive. */
+  assert( iReg>0 || pParse->nErr || pParse->db->mallocFailed );
+  assert( iCol>=-1 && iCol<32768 );  /* Finite column numbers */
+
+  /* The SQLITE_ColumnCache flag disables the column cache.  This is used
+  ** for testing only - to verify that SQLite always gets the same answer
+  ** with and without the column cache.
+  */
+  if( OptimizationDisabled(pParse->db, SQLITE_ColumnCache) ) return;
+
+  /* First replace any existing entry.
+  **
+  ** Actually, the way the column cache is currently used, we are guaranteed
+  ** that the object will never already be in cache.  Verify this guarantee.
+  */
+#ifndef NDEBUG
+  for(i=0, p=pParse->aColCache; i<pParse->nColCache; i++, p++){
+    assert( p->iTable!=iTab || p->iColumn!=iCol );
+  }
+#endif
+
+  /* If the cache is already full, delete the least recently used entry */
+  if( pParse->nColCache>=SQLITE_N_COLCACHE ){
+    minLru = 0x7fffffff;
+    idxLru = -1;
+    for(i=0, p=pParse->aColCache; i<SQLITE_N_COLCACHE; i++, p++){
+      if( p->lru<minLru ){
+        idxLru = i;
+        minLru = p->lru;
+      }
+    }
+    p = &pParse->aColCache[idxLru];
+  }else{
+    p = &pParse->aColCache[pParse->nColCache++];
+  }
+
+  /* Add the new entry to the end of the cache */
+  p->iLevel = pParse->iCacheLevel;
+  p->iTable = iTab;
+  p->iColumn = iCol;
+  p->iReg = iReg;
+  p->tempReg = 0;
+  p->lru = pParse->iCacheCnt++;
+}
+
+/*
+** Indicate that registers between iReg..iReg+nReg-1 are being overwritten.
+** Purge the range of registers from the column cache.
+*/
+void sqlite3ExprCacheRemove(Parse *pParse, int iReg, int nReg){
+  int i = 0;
+  while( i<pParse->nColCache ){
+    struct yColCache *p = &pParse->aColCache[i];
+    if( p->iReg >= iReg && p->iReg < iReg+nReg ){
+      cacheEntryClear(pParse, i);
+    }else{
+      i++;
+    }
+  }
+}
+
+/*
+** Remember the current column cache context.  Any new entries added
+** added to the column cache after this call are removed when the
+** corresponding pop occurs.
+*/
+void sqlite3ExprCachePush(Parse *pParse){
+  pParse->iCacheLevel++;
+#ifdef SQLITE_DEBUG
+  if( pParse->db->flags & SQLITE_VdbeAddopTrace ){
+    printf("PUSH to %d\n", pParse->iCacheLevel);
+  }
+#endif
+}
+
+/*
+** Remove from the column cache any entries that were added since the
+** the previous sqlite3ExprCachePush operation.  In other words, restore
+** the cache to the state it was in prior the most recent Push.
+*/
+void sqlite3ExprCachePop(Parse *pParse){
+  int i = 0;
+  assert( pParse->iCacheLevel>=1 );
+  pParse->iCacheLevel--;
+#ifdef SQLITE_DEBUG
+  if( pParse->db->flags & SQLITE_VdbeAddopTrace ){
+    printf("POP  to %d\n", pParse->iCacheLevel);
+  }
+#endif
+  while( i<pParse->nColCache ){
+    if( pParse->aColCache[i].iLevel>pParse->iCacheLevel ){
+      cacheEntryClear(pParse, i);
+    }else{
+      i++;
+    }
+  }
+}
+
+/*
+** When a cached column is reused, make sure that its register is
+** no longer available as a temp register.  ticket #3879:  that same
+** register might be in the cache in multiple places, so be sure to
+** get them all.
+*/
+static void sqlite3ExprCachePinRegister(Parse *pParse, int iReg){
+  int i;
+  struct yColCache *p;
+  for(i=0, p=pParse->aColCache; i<pParse->nColCache; i++, p++){
+    if( p->iReg==iReg ){
+      p->tempReg = 0;
+    }
+  }
+}
+
+/* Generate code that will load into register regOut a value that is
+** appropriate for the iIdxCol-th column of index pIdx.
+*/
+void sqlite3ExprCodeLoadIndexColumn(
+  Parse *pParse,  /* The parsing context */
+  Index *pIdx,    /* The index whose column is to be loaded */
+  int iTabCur,    /* Cursor pointing to a table row */
+  int iIdxCol,    /* The column of the index to be loaded */
+  int regOut      /* Store the index column value in this register */
+){
+  i16 iTabCol = pIdx->aiColumn[iIdxCol];
+  if( iTabCol==XN_EXPR ){
+    assert( pIdx->aColExpr );
+    assert( pIdx->aColExpr->nExpr>iIdxCol );
+    pParse->iSelfTab = iTabCur;
+    sqlite3ExprCodeCopy(pParse, pIdx->aColExpr->a[iIdxCol].pExpr, regOut);
+  }else{
+    sqlite3ExprCodeGetColumnOfTable(pParse->pVdbe, pIdx->pTable, iTabCur,
+                                    iTabCol, regOut);
+  }
+}
+
+/*
+** Generate code to extract the value of the iCol-th column of a table.
+*/
+void sqlite3ExprCodeGetColumnOfTable(
+  Vdbe *v,        /* The VDBE under construction */
+  Table *pTab,    /* The table containing the value */
+  int iTabCur,    /* The table cursor.  Or the PK cursor for WITHOUT ROWID */
+  int iCol,       /* Index of the column to extract */
+  int regOut      /* Extract the value into this register */
+){
+  if( iCol<0 || iCol==pTab->iPKey ){
+    sqlite3VdbeAddOp2(v, OP_Rowid, iTabCur, regOut);
+  }else{
+    int op = IsVirtual(pTab) ? OP_VColumn : OP_Column;
+    int x = iCol;
+    if( !HasRowid(pTab) && !IsVirtual(pTab) ){
+      x = sqlite3ColumnOfIndex(sqlite3PrimaryKeyIndex(pTab), iCol);
+    }
+    sqlite3VdbeAddOp3(v, op, iTabCur, x, regOut);
+  }
+  if( iCol>=0 ){
+    sqlite3ColumnDefault(v, pTab, iCol, regOut);
+  }
+}
+
+/*
+** Generate code that will extract the iColumn-th column from
+** table pTab and store the column value in a register. 
+**
+** An effort is made to store the column value in register iReg.  This
+** is not garanteeed for GetColumn() - the result can be stored in
+** any register.  But the result is guaranteed to land in register iReg
+** for GetColumnToReg().
+**
+** There must be an open cursor to pTab in iTable when this routine
+** is called.  If iColumn<0 then code is generated that extracts the rowid.
+*/
+int sqlite3ExprCodeGetColumn(
+  Parse *pParse,   /* Parsing and code generating context */
+  Table *pTab,     /* Description of the table we are reading from */
+  int iColumn,     /* Index of the table column */
+  int iTable,      /* The cursor pointing to the table */
+  int iReg,        /* Store results here */
+  u8 p5            /* P5 value for OP_Column + FLAGS */
+){
+  Vdbe *v = pParse->pVdbe;
+  int i;
+  struct yColCache *p;
+
+  for(i=0, p=pParse->aColCache; i<pParse->nColCache; i++, p++){
+    if( p->iTable==iTable && p->iColumn==iColumn ){
+      p->lru = pParse->iCacheCnt++;
+      sqlite3ExprCachePinRegister(pParse, p->iReg);
+      return p->iReg;
+    }
+  }  
+  assert( v!=0 );
+  sqlite3ExprCodeGetColumnOfTable(v, pTab, iTable, iColumn, iReg);
+  if( p5 ){
+    sqlite3VdbeChangeP5(v, p5);
+  }else{   
+    sqlite3ExprCacheStore(pParse, iTable, iColumn, iReg);
+  }
+  return iReg;
+}
+void sqlite3ExprCodeGetColumnToReg(
+  Parse *pParse,   /* Parsing and code generating context */
+  Table *pTab,     /* Description of the table we are reading from */
+  int iColumn,     /* Index of the table column */
+  int iTable,      /* The cursor pointing to the table */
+  int iReg         /* Store results here */
+){
+  int r1 = sqlite3ExprCodeGetColumn(pParse, pTab, iColumn, iTable, iReg, 0);
+  if( r1!=iReg ) sqlite3VdbeAddOp2(pParse->pVdbe, OP_SCopy, r1, iReg);
+}
+
+
+/*
+** Clear all column cache entries.
+*/
+void sqlite3ExprCacheClear(Parse *pParse){
+  int i;
+
+#if SQLITE_DEBUG
+  if( pParse->db->flags & SQLITE_VdbeAddopTrace ){
+    printf("CLEAR\n");
+  }
+#endif
+  for(i=0; i<pParse->nColCache; i++){
+    if( pParse->aColCache[i].tempReg
+     && pParse->nTempReg<ArraySize(pParse->aTempReg)
+    ){
+       pParse->aTempReg[pParse->nTempReg++] = pParse->aColCache[i].iReg;
+    }
+  }
+  pParse->nColCache = 0;
+}
+
+/*
+** Record the fact that an affinity change has occurred on iCount
+** registers starting with iStart.
+*/
+void sqlite3ExprCacheAffinityChange(Parse *pParse, int iStart, int iCount){
+  sqlite3ExprCacheRemove(pParse, iStart, iCount);
+}
+
+/*
+** Generate code to move content from registers iFrom...iFrom+nReg-1
+** over to iTo..iTo+nReg-1. Keep the column cache up-to-date.
+*/
+void sqlite3ExprCodeMove(Parse *pParse, int iFrom, int iTo, int nReg){
+  assert( iFrom>=iTo+nReg || iFrom+nReg<=iTo );
+  sqlite3VdbeAddOp3(pParse->pVdbe, OP_Move, iFrom, iTo, nReg);
+  sqlite3ExprCacheRemove(pParse, iFrom, nReg);
+}
+
+#if defined(SQLITE_DEBUG) || defined(SQLITE_COVERAGE_TEST)
+/*
+** Return true if any register in the range iFrom..iTo (inclusive)
+** is used as part of the column cache.
+**
+** This routine is used within assert() and testcase() macros only
+** and does not appear in a normal build.
+*/
+static int usedAsColumnCache(Parse *pParse, int iFrom, int iTo){
+  int i;
+  struct yColCache *p;
+  for(i=0, p=pParse->aColCache; i<pParse->nColCache; i++, p++){
+    int r = p->iReg;
+    if( r>=iFrom && r<=iTo ) return 1;    /*NO_TEST*/
+  }
+  return 0;
+}
+#endif /* SQLITE_DEBUG || SQLITE_COVERAGE_TEST */
+
+
+/*
+** Convert a scalar expression node to a TK_REGISTER referencing
+** register iReg.  The caller must ensure that iReg already contains
+** the correct value for the expression.
+*/
+static void exprToRegister(Expr *p, int iReg){
+  p->op2 = p->op;
+  p->op = TK_REGISTER;
+  p->iTable = iReg;
+  ExprClearProperty(p, EP_Skip);
+}
+
+/*
+** Evaluate an expression (either a vector or a scalar expression) and store
+** the result in continguous temporary registers.  Return the index of
+** the first register used to store the result.
+**
+** If the returned result register is a temporary scalar, then also write
+** that register number into *piFreeable.  If the returned result register
+** is not a temporary or if the expression is a vector set *piFreeable
+** to 0.
+*/
+static int exprCodeVector(Parse *pParse, Expr *p, int *piFreeable){
+  int iResult;
+  int nResult = sqlite3ExprVectorSize(p);
+  if( nResult==1 ){
+    iResult = sqlite3ExprCodeTemp(pParse, p, piFreeable);
+  }else{
+    *piFreeable = 0;
+    if( p->op==TK_SELECT ){
+      iResult = sqlite3CodeSubselect(pParse, p, 0, 0);
+    }else{
+      int i;
+      iResult = pParse->nMem+1;
+      pParse->nMem += nResult;
+      for(i=0; i<nResult; i++){
+        sqlite3ExprCodeFactorable(pParse, p->x.pList->a[i].pExpr, i+iResult);
+      }
+    }
+  }
+  return iResult;
+}
+
+
+/*
+** Generate code into the current Vdbe to evaluate the given
+** expression.  Attempt to store the results in register "target".
+** Return the register where results are stored.
+**
+** With this routine, there is no guarantee that results will
+** be stored in target.  The result might be stored in some other
+** register if it is convenient to do so.  The calling function
+** must check the return code and move the results to the desired
+** register.
+*/
+int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target){
+  Vdbe *v = pParse->pVdbe;  /* The VM under construction */
+  int op;                   /* The opcode being coded */
+  int inReg = target;       /* Results stored in register inReg */
+  int regFree1 = 0;         /* If non-zero free this temporary register */
+  int regFree2 = 0;         /* If non-zero free this temporary register */
+  int r1, r2;               /* Various register numbers */
+  Expr tempX;               /* Temporary expression node */
+  int p5 = 0;
+
+  assert( target>0 && target<=pParse->nMem );
+  if( v==0 ){
+    assert( pParse->db->mallocFailed );
+    return 0;
+  }
+
+  if( pExpr==0 ){
+    op = TK_NULL;
+  }else{
+    op = pExpr->op;
+  }
+  switch( op ){
+    case TK_AGG_COLUMN: {
+      AggInfo *pAggInfo = pExpr->pAggInfo;
+      struct AggInfo_col *pCol = &pAggInfo->aCol[pExpr->iAgg];
+      if( !pAggInfo->directMode ){
+        assert( pCol->iMem>0 );
+        return pCol->iMem;
+      }else if( pAggInfo->useSortingIdx ){
+        sqlite3VdbeAddOp3(v, OP_Column, pAggInfo->sortingIdxPTab,
+                              pCol->iSorterColumn, target);
+        return target;
+      }
+      /* Otherwise, fall thru into the TK_COLUMN case */
+    }
+    case TK_COLUMN: {
+      int iTab = pExpr->iTable;
+      if( iTab<0 ){
+        if( pParse->ckBase>0 ){
+          /* Generating CHECK constraints or inserting into partial index */
+          return pExpr->iColumn + pParse->ckBase;
+        }else{
+          /* Coding an expression that is part of an index where column names
+          ** in the index refer to the table to which the index belongs */
+          iTab = pParse->iSelfTab;
+        }
+      }
+      return sqlite3ExprCodeGetColumn(pParse, pExpr->pTab,
+                               pExpr->iColumn, iTab, target,
+                               pExpr->op2);
+    }
+    case TK_INTEGER: {
+      codeInteger(pParse, pExpr, 0, target);
+      return target;
+    }
+#ifndef SQLITE_OMIT_FLOATING_POINT
+    case TK_FLOAT: {
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      codeReal(v, pExpr->u.zToken, 0, target);
+      return target;
+    }
+#endif
+    case TK_STRING: {
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      sqlite3VdbeLoadString(v, target, pExpr->u.zToken);
+      return target;
+    }
+    case TK_NULL: {
+      sqlite3VdbeAddOp2(v, OP_Null, 0, target);
+      return target;
+    }
+#ifndef SQLITE_OMIT_BLOB_LITERAL
+    case TK_BLOB: {
+      int n;
+      const char *z;
+      char *zBlob;
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      assert( pExpr->u.zToken[0]=='x' || pExpr->u.zToken[0]=='X' );
+      assert( pExpr->u.zToken[1]=='\'' );
+      z = &pExpr->u.zToken[2];
+      n = sqlite3Strlen30(z) - 1;
+      assert( z[n]=='\'' );
+      zBlob = sqlite3HexToBlob(sqlite3VdbeDb(v), z, n);
+      sqlite3VdbeAddOp4(v, OP_Blob, n/2, target, 0, zBlob, P4_DYNAMIC);
+      return target;
+    }
+#endif
+    case TK_VARIABLE: {
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      assert( pExpr->u.zToken!=0 );
+      assert( pExpr->u.zToken[0]!=0 );
+      sqlite3VdbeAddOp2(v, OP_Variable, pExpr->iColumn, target);
+      if( pExpr->u.zToken[1]!=0 ){
+        const char *z = sqlite3VListNumToName(pParse->pVList, pExpr->iColumn);
+        assert( pExpr->u.zToken[0]=='?' || strcmp(pExpr->u.zToken, z)==0 );
+        pParse->pVList[0] = 0; /* Indicate VList may no longer be enlarged */
+        sqlite3VdbeAppendP4(v, (char*)z, P4_STATIC);
+      }
+      return target;
+    }
+    case TK_REGISTER: {
+      return pExpr->iTable;
+    }
+#ifndef SQLITE_OMIT_CAST
+    case TK_CAST: {
+      /* Expressions of the form:   CAST(pLeft AS token) */
+      inReg = sqlite3ExprCodeTarget(pParse, pExpr->pLeft, target);
+      if( inReg!=target ){
+        sqlite3VdbeAddOp2(v, OP_SCopy, inReg, target);
+        inReg = target;
+      }
+      sqlite3VdbeAddOp2(v, OP_Cast, target,
+                        sqlite3AffinityType(pExpr->u.zToken, 0));
+      testcase( usedAsColumnCache(pParse, inReg, inReg) );
+      sqlite3ExprCacheAffinityChange(pParse, inReg, 1);
+      return inReg;
+    }
+#endif /* SQLITE_OMIT_CAST */
+    case TK_IS:
+    case TK_ISNOT:
+      op = (op==TK_IS) ? TK_EQ : TK_NE;
+      p5 = SQLITE_NULLEQ;
+      /* fall-through */
+    case TK_LT:
+    case TK_LE:
+    case TK_GT:
+    case TK_GE:
+    case TK_NE:
+    case TK_EQ: {
+      Expr *pLeft = pExpr->pLeft;
+      if( sqlite3ExprIsVector(pLeft) ){
+        codeVectorCompare(pParse, pExpr, target, op, p5);
+      }else{
+        r1 = sqlite3ExprCodeTemp(pParse, pLeft, &regFree1);
+        r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, &regFree2);
+        codeCompare(pParse, pLeft, pExpr->pRight, op,
+            r1, r2, inReg, SQLITE_STOREP2 | p5);
+        assert(TK_LT==OP_Lt); testcase(op==OP_Lt); VdbeCoverageIf(v,op==OP_Lt);
+        assert(TK_LE==OP_Le); testcase(op==OP_Le); VdbeCoverageIf(v,op==OP_Le);
+        assert(TK_GT==OP_Gt); testcase(op==OP_Gt); VdbeCoverageIf(v,op==OP_Gt);
+        assert(TK_GE==OP_Ge); testcase(op==OP_Ge); VdbeCoverageIf(v,op==OP_Ge);
+        assert(TK_EQ==OP_Eq); testcase(op==OP_Eq); VdbeCoverageIf(v,op==OP_Eq);
+        assert(TK_NE==OP_Ne); testcase(op==OP_Ne); VdbeCoverageIf(v,op==OP_Ne);
+        testcase( regFree1==0 );
+        testcase( regFree2==0 );
+      }
+      break;
+    }
+    case TK_AND:
+    case TK_OR:
+    case TK_PLUS:
+    case TK_STAR:
+    case TK_MINUS:
+    case TK_REM:
+    case TK_BITAND:
+    case TK_BITOR:
+    case TK_SLASH:
+    case TK_LSHIFT:
+    case TK_RSHIFT: 
+    case TK_CONCAT: {
+      assert( TK_AND==OP_And );            testcase( op==TK_AND );
+      assert( TK_OR==OP_Or );              testcase( op==TK_OR );
+      assert( TK_PLUS==OP_Add );           testcase( op==TK_PLUS );
+      assert( TK_MINUS==OP_Subtract );     testcase( op==TK_MINUS );
+      assert( TK_REM==OP_Remainder );      testcase( op==TK_REM );
+      assert( TK_BITAND==OP_BitAnd );      testcase( op==TK_BITAND );
+      assert( TK_BITOR==OP_BitOr );        testcase( op==TK_BITOR );
+      assert( TK_SLASH==OP_Divide );       testcase( op==TK_SLASH );
+      assert( TK_LSHIFT==OP_ShiftLeft );   testcase( op==TK_LSHIFT );
+      assert( TK_RSHIFT==OP_ShiftRight );  testcase( op==TK_RSHIFT );
+      assert( TK_CONCAT==OP_Concat );      testcase( op==TK_CONCAT );
+      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
+      r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, &regFree2);
+      sqlite3VdbeAddOp3(v, op, r2, r1, target);
+      testcase( regFree1==0 );
+      testcase( regFree2==0 );
+      break;
+    }
+    case TK_UMINUS: {
+      Expr *pLeft = pExpr->pLeft;
+      assert( pLeft );
+      if( pLeft->op==TK_INTEGER ){
+        codeInteger(pParse, pLeft, 1, target);
+        return target;
+#ifndef SQLITE_OMIT_FLOATING_POINT
+      }else if( pLeft->op==TK_FLOAT ){
+        assert( !ExprHasProperty(pExpr, EP_IntValue) );
+        codeReal(v, pLeft->u.zToken, 1, target);
+        return target;
+#endif
+      }else{
+        tempX.op = TK_INTEGER;
+        tempX.flags = EP_IntValue|EP_TokenOnly;
+        tempX.u.iValue = 0;
+        r1 = sqlite3ExprCodeTemp(pParse, &tempX, &regFree1);
+        r2 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree2);
+        sqlite3VdbeAddOp3(v, OP_Subtract, r2, r1, target);
+        testcase( regFree2==0 );
+      }
+      break;
+    }
+    case TK_BITNOT:
+    case TK_NOT: {
+      assert( TK_BITNOT==OP_BitNot );   testcase( op==TK_BITNOT );
+      assert( TK_NOT==OP_Not );         testcase( op==TK_NOT );
+      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
+      testcase( regFree1==0 );
+      sqlite3VdbeAddOp2(v, op, r1, inReg);
+      break;
+    }
+    case TK_ISNULL:
+    case TK_NOTNULL: {
+      int addr;
+      assert( TK_ISNULL==OP_IsNull );   testcase( op==TK_ISNULL );
+      assert( TK_NOTNULL==OP_NotNull ); testcase( op==TK_NOTNULL );
+      sqlite3VdbeAddOp2(v, OP_Integer, 1, target);
+      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
+      testcase( regFree1==0 );
+      addr = sqlite3VdbeAddOp1(v, op, r1);
+      VdbeCoverageIf(v, op==TK_ISNULL);
+      VdbeCoverageIf(v, op==TK_NOTNULL);
+      sqlite3VdbeAddOp2(v, OP_Integer, 0, target);
+      sqlite3VdbeJumpHere(v, addr);
+      break;
+    }
+    case TK_AGG_FUNCTION: {
+      AggInfo *pInfo = pExpr->pAggInfo;
+      if( pInfo==0 ){
+        assert( !ExprHasProperty(pExpr, EP_IntValue) );
+        sqlite3ErrorMsg(pParse, "misuse of aggregate: %s()", pExpr->u.zToken);
+      }else{
+        return pInfo->aFunc[pExpr->iAgg].iMem;
+      }
+      break;
+    }
+    case TK_FUNCTION: {
+      ExprList *pFarg;       /* List of function arguments */
+      int nFarg;             /* Number of function arguments */
+      FuncDef *pDef;         /* The function definition object */
+      const char *zId;       /* The function name */
+      u32 constMask = 0;     /* Mask of function arguments that are constant */
+      int i;                 /* Loop counter */
+      sqlite3 *db = pParse->db;  /* The database connection */
+      u8 enc = ENC(db);      /* The text encoding used by this database */
+      CollSeq *pColl = 0;    /* A collating sequence */
+
+      if( ConstFactorOk(pParse) && sqlite3ExprIsConstantNotJoin(pExpr) ){
+        /* SQL functions can be expensive. So try to move constant functions
+        ** out of the inner loop, even if that means an extra OP_Copy. */
+        return sqlite3ExprCodeAtInit(pParse, pExpr, -1);
+      }
+      assert( !ExprHasProperty(pExpr, EP_xIsSelect) );
+      if( ExprHasProperty(pExpr, EP_TokenOnly) ){
+        pFarg = 0;
+      }else{
+        pFarg = pExpr->x.pList;
+      }
+      nFarg = pFarg ? pFarg->nExpr : 0;
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      zId = pExpr->u.zToken;
+      pDef = sqlite3FindFunction(db, zId, nFarg, enc, 0);
+#ifdef SQLITE_ENABLE_UNKNOWN_SQL_FUNCTION
+      if( pDef==0 && pParse->explain ){
+        pDef = sqlite3FindFunction(db, "unknown", nFarg, enc, 0);
+      }
+#endif
+      if( pDef==0 || pDef->xFinalize!=0 ){
+        sqlite3ErrorMsg(pParse, "unknown function: %s()", zId);
+        break;
+      }
+
+      /* Attempt a direct implementation of the built-in COALESCE() and
+      ** IFNULL() functions.  This avoids unnecessary evaluation of
+      ** arguments past the first non-NULL argument.
+      */
+      if( pDef->funcFlags & SQLITE_FUNC_COALESCE ){
+        int endCoalesce = sqlite3VdbeMakeLabel(v);
+        assert( nFarg>=2 );
+        sqlite3ExprCode(pParse, pFarg->a[0].pExpr, target);
+        for(i=1; i<nFarg; i++){
+          sqlite3VdbeAddOp2(v, OP_NotNull, target, endCoalesce);
+          VdbeCoverage(v);
+          sqlite3ExprCacheRemove(pParse, target, 1);
+          sqlite3ExprCachePush(pParse);
+          sqlite3ExprCode(pParse, pFarg->a[i].pExpr, target);
+          sqlite3ExprCachePop(pParse);
+        }
+        sqlite3VdbeResolveLabel(v, endCoalesce);
+        break;
+      }
+
+      /* The UNLIKELY() function is a no-op.  The result is the value
+      ** of the first argument.
+      */
+      if( pDef->funcFlags & SQLITE_FUNC_UNLIKELY ){
+        assert( nFarg>=1 );
+        return sqlite3ExprCodeTarget(pParse, pFarg->a[0].pExpr, target);
+      }
+
+#ifdef SQLITE_DEBUG
+      /* The AFFINITY() function evaluates to a string that describes
+      ** the type affinity of the argument.  This is used for testing of
+      ** the SQLite type logic.
+      */
+      if( pDef->funcFlags & SQLITE_FUNC_AFFINITY ){
+        const char *azAff[] = { "blob", "text", "numeric", "integer", "real" };
+        char aff;
+        assert( nFarg==1 );
+        aff = sqlite3ExprAffinity(pFarg->a[0].pExpr);
+        sqlite3VdbeLoadString(v, target, 
+                              aff ? azAff[aff-SQLITE_AFF_BLOB] : "none");
+        return target;
+      }
+#endif
+
+      for(i=0; i<nFarg; i++){
+        if( i<32 && sqlite3ExprIsConstant(pFarg->a[i].pExpr) ){
+          testcase( i==31 );
+          constMask |= MASKBIT32(i);
+        }
+        if( (pDef->funcFlags & SQLITE_FUNC_NEEDCOLL)!=0 && !pColl ){
+          pColl = sqlite3ExprCollSeq(pParse, pFarg->a[i].pExpr);
+        }
+      }
+      if( pFarg ){
+        if( constMask ){
+          r1 = pParse->nMem+1;
+          pParse->nMem += nFarg;
+        }else{
+          r1 = sqlite3GetTempRange(pParse, nFarg);
+        }
+
+        /* For length() and typeof() functions with a column argument,
+        ** set the P5 parameter to the OP_Column opcode to OPFLAG_LENGTHARG
+        ** or OPFLAG_TYPEOFARG respectively, to avoid unnecessary data
+        ** loading.
+        */
+        if( (pDef->funcFlags & (SQLITE_FUNC_LENGTH|SQLITE_FUNC_TYPEOF))!=0 ){
+          u8 exprOp;
+          assert( nFarg==1 );
+          assert( pFarg->a[0].pExpr!=0 );
+          exprOp = pFarg->a[0].pExpr->op;
+          if( exprOp==TK_COLUMN || exprOp==TK_AGG_COLUMN ){
+            assert( SQLITE_FUNC_LENGTH==OPFLAG_LENGTHARG );
+            assert( SQLITE_FUNC_TYPEOF==OPFLAG_TYPEOFARG );
+            testcase( pDef->funcFlags & OPFLAG_LENGTHARG );
+            pFarg->a[0].pExpr->op2 = 
+                  pDef->funcFlags & (OPFLAG_LENGTHARG|OPFLAG_TYPEOFARG);
+          }
+        }
+
+        sqlite3ExprCachePush(pParse);     /* Ticket 2ea2425d34be */
+        sqlite3ExprCodeExprList(pParse, pFarg, r1, 0,
+                                SQLITE_ECEL_DUP|SQLITE_ECEL_FACTOR);
+        sqlite3ExprCachePop(pParse);      /* Ticket 2ea2425d34be */
+      }else{
+        r1 = 0;
+      }
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+      /* Possibly overload the function if the first argument is
+      ** a virtual table column.
+      **
+      ** For infix functions (LIKE, GLOB, REGEXP, and MATCH) use the
+      ** second argument, not the first, as the argument to test to
+      ** see if it is a column in a virtual table.  This is done because
+      ** the left operand of infix functions (the operand we want to
+      ** control overloading) ends up as the second argument to the
+      ** function.  The expression "A glob B" is equivalent to 
+      ** "glob(B,A).  We want to use the A in "A glob B" to test
+      ** for function overloading.  But we use the B term in "glob(B,A)".
+      */
+      if( nFarg>=2 && (pExpr->flags & EP_InfixFunc) ){
+        pDef = sqlite3VtabOverloadFunction(db, pDef, nFarg, pFarg->a[1].pExpr);
+      }else if( nFarg>0 ){
+        pDef = sqlite3VtabOverloadFunction(db, pDef, nFarg, pFarg->a[0].pExpr);
+      }
+#endif
+      if( pDef->funcFlags & SQLITE_FUNC_NEEDCOLL ){
+        if( !pColl ) pColl = db->pDfltColl; 
+        sqlite3VdbeAddOp4(v, OP_CollSeq, 0, 0, 0, (char *)pColl, P4_COLLSEQ);
+      }
+      sqlite3VdbeAddOp4(v, OP_Function0, constMask, r1, target,
+                        (char*)pDef, P4_FUNCDEF);
+      sqlite3VdbeChangeP5(v, (u8)nFarg);
+      if( nFarg && constMask==0 ){
+        sqlite3ReleaseTempRange(pParse, r1, nFarg);
+      }
+      return target;
+    }
+#ifndef SQLITE_OMIT_SUBQUERY
+    case TK_EXISTS:
+    case TK_SELECT: {
+      int nCol;
+      testcase( op==TK_EXISTS );
+      testcase( op==TK_SELECT );
+      if( op==TK_SELECT && (nCol = pExpr->x.pSelect->pEList->nExpr)!=1 ){
+        sqlite3SubselectError(pParse, nCol, 1);
+      }else{
+        return sqlite3CodeSubselect(pParse, pExpr, 0, 0);
+      }
+      break;
+    }
+    case TK_SELECT_COLUMN: {
+      int n;
+      if( pExpr->pLeft->iTable==0 ){
+        pExpr->pLeft->iTable = sqlite3CodeSubselect(pParse, pExpr->pLeft, 0, 0);
+      }
+      assert( pExpr->iTable==0 || pExpr->pLeft->op==TK_SELECT );
+      if( pExpr->iTable
+       && pExpr->iTable!=(n = sqlite3ExprVectorSize(pExpr->pLeft)) 
+      ){
+        sqlite3ErrorMsg(pParse, "%d columns assigned %d values",
+                                pExpr->iTable, n);
+      }
+      return pExpr->pLeft->iTable + pExpr->iColumn;
+    }
+    case TK_IN: {
+      int destIfFalse = sqlite3VdbeMakeLabel(v);
+      int destIfNull = sqlite3VdbeMakeLabel(v);
+      sqlite3VdbeAddOp2(v, OP_Null, 0, target);
+      sqlite3ExprCodeIN(pParse, pExpr, destIfFalse, destIfNull);
+      sqlite3VdbeAddOp2(v, OP_Integer, 1, target);
+      sqlite3VdbeResolveLabel(v, destIfFalse);
+      sqlite3VdbeAddOp2(v, OP_AddImm, target, 0);
+      sqlite3VdbeResolveLabel(v, destIfNull);
+      return target;
+    }
+#endif /* SQLITE_OMIT_SUBQUERY */
+
+
+    /*
+    **    x BETWEEN y AND z
+    **
+    ** This is equivalent to
+    **
+    **    x>=y AND x<=z
+    **
+    ** X is stored in pExpr->pLeft.
+    ** Y is stored in pExpr->pList->a[0].pExpr.
+    ** Z is stored in pExpr->pList->a[1].pExpr.
+    */
+    case TK_BETWEEN: {
+      exprCodeBetween(pParse, pExpr, target, 0, 0);
+      return target;
+    }
+    case TK_SPAN:
+    case TK_COLLATE: 
+    case TK_UPLUS: {
+      return sqlite3ExprCodeTarget(pParse, pExpr->pLeft, target);
+    }
+
+    case TK_TRIGGER: {
+      /* If the opcode is TK_TRIGGER, then the expression is a reference
+      ** to a column in the new.* or old.* pseudo-tables available to
+      ** trigger programs. In this case Expr.iTable is set to 1 for the
+      ** new.* pseudo-table, or 0 for the old.* pseudo-table. Expr.iColumn
+      ** is set to the column of the pseudo-table to read, or to -1 to
+      ** read the rowid field.
+      **
+      ** The expression is implemented using an OP_Param opcode. The p1
+      ** parameter is set to 0 for an old.rowid reference, or to (i+1)
+      ** to reference another column of the old.* pseudo-table, where 
+      ** i is the index of the column. For a new.rowid reference, p1 is
+      ** set to (n+1), where n is the number of columns in each pseudo-table.
+      ** For a reference to any other column in the new.* pseudo-table, p1
+      ** is set to (n+2+i), where n and i are as defined previously. For
+      ** example, if the table on which triggers are being fired is
+      ** declared as:
+      **
+      **   CREATE TABLE t1(a, b);
+      **
+      ** Then p1 is interpreted as follows:
+      **
+      **   p1==0   ->    old.rowid     p1==3   ->    new.rowid
+      **   p1==1   ->    old.a         p1==4   ->    new.a
+      **   p1==2   ->    old.b         p1==5   ->    new.b       
+      */
+      Table *pTab = pExpr->pTab;
+      int p1 = pExpr->iTable * (pTab->nCol+1) + 1 + pExpr->iColumn;
+
+      assert( pExpr->iTable==0 || pExpr->iTable==1 );
+      assert( pExpr->iColumn>=-1 && pExpr->iColumn<pTab->nCol );
+      assert( pTab->iPKey<0 || pExpr->iColumn!=pTab->iPKey );
+      assert( p1>=0 && p1<(pTab->nCol*2+2) );
+
+      sqlite3VdbeAddOp2(v, OP_Param, p1, target);
+      VdbeComment((v, "%s.%s -> $%d",
+        (pExpr->iTable ? "new" : "old"),
+        (pExpr->iColumn<0 ? "rowid" : pExpr->pTab->aCol[pExpr->iColumn].zName),
+        target
+      ));
+
+#ifndef SQLITE_OMIT_FLOATING_POINT
+      /* If the column has REAL affinity, it may currently be stored as an
+      ** integer. Use OP_RealAffinity to make sure it is really real.
+      **
+      ** EVIDENCE-OF: R-60985-57662 SQLite will convert the value back to
+      ** floating point when extracting it from the record.  */
+      if( pExpr->iColumn>=0 
+       && pTab->aCol[pExpr->iColumn].affinity==SQLITE_AFF_REAL
+      ){
+        sqlite3VdbeAddOp1(v, OP_RealAffinity, target);
+      }
+#endif
+      break;
+    }
+
+    case TK_VECTOR: {
+      sqlite3ErrorMsg(pParse, "row value misused");
+      break;
+    }
+
+    /*
+    ** Form A:
+    **   CASE x WHEN e1 THEN r1 WHEN e2 THEN r2 ... WHEN eN THEN rN ELSE y END
+    **
+    ** Form B:
+    **   CASE WHEN e1 THEN r1 WHEN e2 THEN r2 ... WHEN eN THEN rN ELSE y END
+    **
+    ** Form A is can be transformed into the equivalent form B as follows:
+    **   CASE WHEN x=e1 THEN r1 WHEN x=e2 THEN r2 ...
+    **        WHEN x=eN THEN rN ELSE y END
+    **
+    ** X (if it exists) is in pExpr->pLeft.
+    ** Y is in the last element of pExpr->x.pList if pExpr->x.pList->nExpr is
+    ** odd.  The Y is also optional.  If the number of elements in x.pList
+    ** is even, then Y is omitted and the "otherwise" result is NULL.
+    ** Ei is in pExpr->pList->a[i*2] and Ri is pExpr->pList->a[i*2+1].
+    **
+    ** The result of the expression is the Ri for the first matching Ei,
+    ** or if there is no matching Ei, the ELSE term Y, or if there is
+    ** no ELSE term, NULL.
+    */
+    default: assert( op==TK_CASE ); {
+      int endLabel;                     /* GOTO label for end of CASE stmt */
+      int nextCase;                     /* GOTO label for next WHEN clause */
+      int nExpr;                        /* 2x number of WHEN terms */
+      int i;                            /* Loop counter */
+      ExprList *pEList;                 /* List of WHEN terms */
+      struct ExprList_item *aListelem;  /* Array of WHEN terms */
+      Expr opCompare;                   /* The X==Ei expression */
+      Expr *pX;                         /* The X expression */
+      Expr *pTest = 0;                  /* X==Ei (form A) or just Ei (form B) */
+      VVA_ONLY( int iCacheLevel = pParse->iCacheLevel; )
+
+      assert( !ExprHasProperty(pExpr, EP_xIsSelect) && pExpr->x.pList );
+      assert(pExpr->x.pList->nExpr > 0);
+      pEList = pExpr->x.pList;
+      aListelem = pEList->a;
+      nExpr = pEList->nExpr;
+      endLabel = sqlite3VdbeMakeLabel(v);
+      if( (pX = pExpr->pLeft)!=0 ){
+        tempX = *pX;
+        testcase( pX->op==TK_COLUMN );
+        exprToRegister(&tempX, exprCodeVector(pParse, &tempX, &regFree1));
+        testcase( regFree1==0 );
+        memset(&opCompare, 0, sizeof(opCompare));
+        opCompare.op = TK_EQ;
+        opCompare.pLeft = &tempX;
+        pTest = &opCompare;
+        /* Ticket b351d95f9cd5ef17e9d9dbae18f5ca8611190001:
+        ** The value in regFree1 might get SCopy-ed into the file result.
+        ** So make sure that the regFree1 register is not reused for other
+        ** purposes and possibly overwritten.  */
+        regFree1 = 0;
+      }
+      for(i=0; i<nExpr-1; i=i+2){
+        sqlite3ExprCachePush(pParse);
+        if( pX ){
+          assert( pTest!=0 );
+          opCompare.pRight = aListelem[i].pExpr;
+        }else{
+          pTest = aListelem[i].pExpr;
+        }
+        nextCase = sqlite3VdbeMakeLabel(v);
+        testcase( pTest->op==TK_COLUMN );
+        sqlite3ExprIfFalse(pParse, pTest, nextCase, SQLITE_JUMPIFNULL);
+        testcase( aListelem[i+1].pExpr->op==TK_COLUMN );
+        sqlite3ExprCode(pParse, aListelem[i+1].pExpr, target);
+        sqlite3VdbeGoto(v, endLabel);
+        sqlite3ExprCachePop(pParse);
+        sqlite3VdbeResolveLabel(v, nextCase);
+      }
+      if( (nExpr&1)!=0 ){
+        sqlite3ExprCachePush(pParse);
+        sqlite3ExprCode(pParse, pEList->a[nExpr-1].pExpr, target);
+        sqlite3ExprCachePop(pParse);
+      }else{
+        sqlite3VdbeAddOp2(v, OP_Null, 0, target);
+      }
+      assert( pParse->db->mallocFailed || pParse->nErr>0 
+           || pParse->iCacheLevel==iCacheLevel );
+      sqlite3VdbeResolveLabel(v, endLabel);
+      break;
+    }
+#ifndef SQLITE_OMIT_TRIGGER
+    case TK_RAISE: {
+      assert( pExpr->affinity==OE_Rollback 
+           || pExpr->affinity==OE_Abort
+           || pExpr->affinity==OE_Fail
+           || pExpr->affinity==OE_Ignore
+      );
+      if( !pParse->pTriggerTab ){
+        sqlite3ErrorMsg(pParse,
+                       "RAISE() may only be used within a trigger-program");
+        return 0;
+      }
+      if( pExpr->affinity==OE_Abort ){
+        sqlite3MayAbort(pParse);
+      }
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      if( pExpr->affinity==OE_Ignore ){
+        sqlite3VdbeAddOp4(
+            v, OP_Halt, SQLITE_OK, OE_Ignore, 0, pExpr->u.zToken,0);
+        VdbeCoverage(v);
+      }else{
+        sqlite3HaltConstraint(pParse, SQLITE_CONSTRAINT_TRIGGER,
+                              pExpr->affinity, pExpr->u.zToken, 0, 0);
+      }
+
+      break;
+    }
+#endif
+  }
+  sqlite3ReleaseTempReg(pParse, regFree1);
+  sqlite3ReleaseTempReg(pParse, regFree2);
+  return inReg;
+}
+
+/*
+** Factor out the code of the given expression to initialization time.
+**
+** If regDest>=0 then the result is always stored in that register and the
+** result is not reusable.  If regDest<0 then this routine is free to 
+** store the value whereever it wants.  The register where the expression 
+** is stored is returned.  When regDest<0, two identical expressions will
+** code to the same register.
+*/
+int sqlite3ExprCodeAtInit(
+  Parse *pParse,    /* Parsing context */
+  Expr *pExpr,      /* The expression to code when the VDBE initializes */
+  int regDest       /* Store the value in this register */
+){
+  ExprList *p;
+  assert( ConstFactorOk(pParse) );
+  p = pParse->pConstExpr;
+  if( regDest<0 && p ){
+    struct ExprList_item *pItem;
+    int i;
+    for(pItem=p->a, i=p->nExpr; i>0; pItem++, i--){
+      if( pItem->reusable && sqlite3ExprCompare(pItem->pExpr,pExpr,-1)==0 ){
+        return pItem->u.iConstExprReg;
+      }
+    }
+  }
+  pExpr = sqlite3ExprDup(pParse->db, pExpr, 0);
+  p = sqlite3ExprListAppend(pParse, p, pExpr);
+  if( p ){
+     struct ExprList_item *pItem = &p->a[p->nExpr-1];
+     pItem->reusable = regDest<0;
+     if( regDest<0 ) regDest = ++pParse->nMem;
+     pItem->u.iConstExprReg = regDest;
+  }
+  pParse->pConstExpr = p;
+  return regDest;
+}
+
+/*
+** Generate code to evaluate an expression and store the results
+** into a register.  Return the register number where the results
+** are stored.
+**
+** If the register is a temporary register that can be deallocated,
+** then write its number into *pReg.  If the result register is not
+** a temporary, then set *pReg to zero.
+**
+** If pExpr is a constant, then this routine might generate this
+** code to fill the register in the initialization section of the
+** VDBE program, in order to factor it out of the evaluation loop.
+*/
+int sqlite3ExprCodeTemp(Parse *pParse, Expr *pExpr, int *pReg){
+  int r2;
+  pExpr = sqlite3ExprSkipCollate(pExpr);
+  if( ConstFactorOk(pParse)
+   && pExpr->op!=TK_REGISTER
+   && sqlite3ExprIsConstantNotJoin(pExpr)
+  ){
+    *pReg  = 0;
+    r2 = sqlite3ExprCodeAtInit(pParse, pExpr, -1);
+  }else{
+    int r1 = sqlite3GetTempReg(pParse);
+    r2 = sqlite3ExprCodeTarget(pParse, pExpr, r1);
+    if( r2==r1 ){
+      *pReg = r1;
+    }else{
+      sqlite3ReleaseTempReg(pParse, r1);
+      *pReg = 0;
+    }
+  }
+  return r2;
+}
+
+/*
+** Generate code that will evaluate expression pExpr and store the
+** results in register target.  The results are guaranteed to appear
+** in register target.
+*/
+void sqlite3ExprCode(Parse *pParse, Expr *pExpr, int target){
+  int inReg;
+
+  assert( target>0 && target<=pParse->nMem );
+  if( pExpr && pExpr->op==TK_REGISTER ){
+    sqlite3VdbeAddOp2(pParse->pVdbe, OP_Copy, pExpr->iTable, target);
+  }else{
+    inReg = sqlite3ExprCodeTarget(pParse, pExpr, target);
+    assert( pParse->pVdbe!=0 || pParse->db->mallocFailed );
+    if( inReg!=target && pParse->pVdbe ){
+      sqlite3VdbeAddOp2(pParse->pVdbe, OP_SCopy, inReg, target);
+    }
+  }
+}
+
+/*
+** Make a transient copy of expression pExpr and then code it using
+** sqlite3ExprCode().  This routine works just like sqlite3ExprCode()
+** except that the input expression is guaranteed to be unchanged.
+*/
+void sqlite3ExprCodeCopy(Parse *pParse, Expr *pExpr, int target){
+  sqlite3 *db = pParse->db;
+  pExpr = sqlite3ExprDup(db, pExpr, 0);
+  if( !db->mallocFailed ) sqlite3ExprCode(pParse, pExpr, target);
+  sqlite3ExprDelete(db, pExpr);
+}
+
+/*
+** Generate code that will evaluate expression pExpr and store the
+** results in register target.  The results are guaranteed to appear
+** in register target.  If the expression is constant, then this routine
+** might choose to code the expression at initialization time.
+*/
+void sqlite3ExprCodeFactorable(Parse *pParse, Expr *pExpr, int target){
+  if( pParse->okConstFactor && sqlite3ExprIsConstant(pExpr) ){
+    sqlite3ExprCodeAtInit(pParse, pExpr, target);
+  }else{
+    sqlite3ExprCode(pParse, pExpr, target);
+  }
+}
+
+/*
+** Generate code that evaluates the given expression and puts the result
+** in register target.
+**
+** Also make a copy of the expression results into another "cache" register
+** and modify the expression so that the next time it is evaluated,
+** the result is a copy of the cache register.
+**
+** This routine is used for expressions that are used multiple 
+** times.  They are evaluated once and the results of the expression
+** are reused.
+*/
+void sqlite3ExprCodeAndCache(Parse *pParse, Expr *pExpr, int target){
+  Vdbe *v = pParse->pVdbe;
+  int iMem;
+
+  assert( target>0 );
+  assert( pExpr->op!=TK_REGISTER );
+  sqlite3ExprCode(pParse, pExpr, target);
+  iMem = ++pParse->nMem;
+  sqlite3VdbeAddOp2(v, OP_Copy, target, iMem);
+  exprToRegister(pExpr, iMem);
+}
+
+/*
+** Generate code that pushes the value of every element of the given
+** expression list into a sequence of registers beginning at target.
+**
+** Return the number of elements evaluated.
+**
+** The SQLITE_ECEL_DUP flag prevents the arguments from being
+** filled using OP_SCopy.  OP_Copy must be used instead.
+**
+** The SQLITE_ECEL_FACTOR argument allows constant arguments to be
+** factored out into initialization code.
+**
+** The SQLITE_ECEL_REF flag means that expressions in the list with
+** ExprList.a[].u.x.iOrderByCol>0 have already been evaluated and stored
+** in registers at srcReg, and so the value can be copied from there.
+*/
+int sqlite3ExprCodeExprList(
+  Parse *pParse,     /* Parsing context */
+  ExprList *pList,   /* The expression list to be coded */
+  int target,        /* Where to write results */
+  int srcReg,        /* Source registers if SQLITE_ECEL_REF */
+  u8 flags           /* SQLITE_ECEL_* flags */
+){
+  struct ExprList_item *pItem;
+  int i, j, n;
+  u8 copyOp = (flags & SQLITE_ECEL_DUP) ? OP_Copy : OP_SCopy;
+  Vdbe *v = pParse->pVdbe;
+  assert( pList!=0 );
+  assert( target>0 );
+  assert( pParse->pVdbe!=0 );  /* Never gets this far otherwise */
+  n = pList->nExpr;
+  if( !ConstFactorOk(pParse) ) flags &= ~SQLITE_ECEL_FACTOR;
+  for(pItem=pList->a, i=0; i<n; i++, pItem++){
+    Expr *pExpr = pItem->pExpr;
+    if( (flags & SQLITE_ECEL_REF)!=0 && (j = pItem->u.x.iOrderByCol)>0 ){
+      if( flags & SQLITE_ECEL_OMITREF ){
+        i--;
+        n--;
+      }else{
+        sqlite3VdbeAddOp2(v, copyOp, j+srcReg-1, target+i);
+      }
+    }else if( (flags & SQLITE_ECEL_FACTOR)!=0 && sqlite3ExprIsConstant(pExpr) ){
+      sqlite3ExprCodeAtInit(pParse, pExpr, target+i);
+    }else{
+      int inReg = sqlite3ExprCodeTarget(pParse, pExpr, target+i);
+      if( inReg!=target+i ){
+        VdbeOp *pOp;
+        if( copyOp==OP_Copy
+         && (pOp=sqlite3VdbeGetOp(v, -1))->opcode==OP_Copy
+         && pOp->p1+pOp->p3+1==inReg
+         && pOp->p2+pOp->p3+1==target+i
+        ){
+          pOp->p3++;
+        }else{
+          sqlite3VdbeAddOp2(v, copyOp, inReg, target+i);
+        }
+      }
+    }
+  }
+  return n;
+}
+
+/*
+** Generate code for a BETWEEN operator.
+**
+**    x BETWEEN y AND z
+**
+** The above is equivalent to 
+**
+**    x>=y AND x<=z
+**
+** Code it as such, taking care to do the common subexpression
+** elimination of x.
+**
+** The xJumpIf parameter determines details:
+**
+**    NULL:                   Store the boolean result in reg[dest]
+**    sqlite3ExprIfTrue:      Jump to dest if true
+**    sqlite3ExprIfFalse:     Jump to dest if false
+**
+** The jumpIfNull parameter is ignored if xJumpIf is NULL.
+*/
+static void exprCodeBetween(
+  Parse *pParse,    /* Parsing and code generating context */
+  Expr *pExpr,      /* The BETWEEN expression */
+  int dest,         /* Jump destination or storage location */
+  void (*xJump)(Parse*,Expr*,int,int), /* Action to take */
+  int jumpIfNull    /* Take the jump if the BETWEEN is NULL */
+){
+ Expr exprAnd;     /* The AND operator in  x>=y AND x<=z  */
+  Expr compLeft;    /* The  x>=y  term */
+  Expr compRight;   /* The  x<=z  term */
+  Expr exprX;       /* The  x  subexpression */
+  int regFree1 = 0; /* Temporary use register */
+
+
+  memset(&compLeft, 0, sizeof(Expr));
+  memset(&compRight, 0, sizeof(Expr));
+  memset(&exprAnd, 0, sizeof(Expr));
+
+  assert( !ExprHasProperty(pExpr, EP_xIsSelect) );
+  exprX = *pExpr->pLeft;
+  exprAnd.op = TK_AND;
+  exprAnd.pLeft = &compLeft;
+  exprAnd.pRight = &compRight;
+  compLeft.op = TK_GE;
+  compLeft.pLeft = &exprX;
+  compLeft.pRight = pExpr->x.pList->a[0].pExpr;
+  compRight.op = TK_LE;
+  compRight.pLeft = &exprX;
+  compRight.pRight = pExpr->x.pList->a[1].pExpr;
+  exprToRegister(&exprX, exprCodeVector(pParse, &exprX, &regFree1));
+  if( xJump ){
+    xJump(pParse, &exprAnd, dest, jumpIfNull);
+  }else{
+    /* Mark the expression is being from the ON or USING clause of a join
+    ** so that the sqlite3ExprCodeTarget() routine will not attempt to move
+    ** it into the Parse.pConstExpr list.  We should use a new bit for this,
+    ** for clarity, but we are out of bits in the Expr.flags field so we
+    ** have to reuse the EP_FromJoin bit.  Bummer. */
+    exprX.flags |= EP_FromJoin;
+    sqlite3ExprCodeTarget(pParse, &exprAnd, dest);
+  }
+  sqlite3ReleaseTempReg(pParse, regFree1);
+
+  /* Ensure adequate test coverage */
+  testcase( xJump==sqlite3ExprIfTrue  && jumpIfNull==0 && regFree1==0 );
+  testcase( xJump==sqlite3ExprIfTrue  && jumpIfNull==0 && regFree1!=0 );
+  testcase( xJump==sqlite3ExprIfTrue  && jumpIfNull!=0 && regFree1==0 );
+  testcase( xJump==sqlite3ExprIfTrue  && jumpIfNull!=0 && regFree1!=0 );
+  testcase( xJump==sqlite3ExprIfFalse && jumpIfNull==0 && regFree1==0 );
+  testcase( xJump==sqlite3ExprIfFalse && jumpIfNull==0 && regFree1!=0 );
+  testcase( xJump==sqlite3ExprIfFalse && jumpIfNull!=0 && regFree1==0 );
+  testcase( xJump==sqlite3ExprIfFalse && jumpIfNull!=0 && regFree1!=0 );
+  testcase( xJump==0 );
+}
+
+/*
+** Generate code for a boolean expression such that a jump is made
+** to the label "dest" if the expression is true but execution
+** continues straight thru if the expression is false.
+**
+** If the expression evaluates to NULL (neither true nor false), then
+** take the jump if the jumpIfNull flag is SQLITE_JUMPIFNULL.
+**
+** This code depends on the fact that certain token values (ex: TK_EQ)
+** are the same as opcode values (ex: OP_Eq) that implement the corresponding
+** operation.  Special comments in vdbe.c and the mkopcodeh.awk script in
+** the make process cause these values to align.  Assert()s in the code
+** below verify that the numbers are aligned correctly.
+*/
+void sqlite3ExprIfTrue(Parse *pParse, Expr *pExpr, int dest, int jumpIfNull){
+  Vdbe *v = pParse->pVdbe;
+  int op = 0;
+  int regFree1 = 0;
+  int regFree2 = 0;
+  int r1, r2;
+
+  assert( jumpIfNull==SQLITE_JUMPIFNULL || jumpIfNull==0 );
+  if( NEVER(v==0) )     return;  /* Existence of VDBE checked by caller */
+  if( NEVER(pExpr==0) ) return;  /* No way this can happen */
+  op = pExpr->op;
+  switch( op ){
+    case TK_AND: {
+      int d2 = sqlite3VdbeMakeLabel(v);
+      testcase( jumpIfNull==0 );
+      sqlite3ExprIfFalse(pParse, pExpr->pLeft, d2,jumpIfNull^SQLITE_JUMPIFNULL);
+      sqlite3ExprCachePush(pParse);
+      sqlite3ExprIfTrue(pParse, pExpr->pRight, dest, jumpIfNull);
+      sqlite3VdbeResolveLabel(v, d2);
+      sqlite3ExprCachePop(pParse);
+      break;
+    }
+    case TK_OR: {
+      testcase( jumpIfNull==0 );
+      sqlite3ExprIfTrue(pParse, pExpr->pLeft, dest, jumpIfNull);
+      sqlite3ExprCachePush(pParse);
+      sqlite3ExprIfTrue(pParse, pExpr->pRight, dest, jumpIfNull);
+      sqlite3ExprCachePop(pParse);
+      break;
+    }
+    case TK_NOT: {
+      testcase( jumpIfNull==0 );
+      sqlite3ExprIfFalse(pParse, pExpr->pLeft, dest, jumpIfNull);
+      break;
+    }
+    case TK_IS:
+    case TK_ISNOT:
+      testcase( op==TK_IS );
+      testcase( op==TK_ISNOT );
+      op = (op==TK_IS) ? TK_EQ : TK_NE;
+      jumpIfNull = SQLITE_NULLEQ;
+      /* Fall thru */
+    case TK_LT:
+    case TK_LE:
+    case TK_GT:
+    case TK_GE:
+    case TK_NE:
+    case TK_EQ: {
+      if( sqlite3ExprIsVector(pExpr->pLeft) ) goto default_expr;
+      testcase( jumpIfNull==0 );
+      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
+      r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, &regFree2);
+      codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op,
+                  r1, r2, dest, jumpIfNull);
+      assert(TK_LT==OP_Lt); testcase(op==OP_Lt); VdbeCoverageIf(v,op==OP_Lt);
+      assert(TK_LE==OP_Le); testcase(op==OP_Le); VdbeCoverageIf(v,op==OP_Le);
+      assert(TK_GT==OP_Gt); testcase(op==OP_Gt); VdbeCoverageIf(v,op==OP_Gt);
+      assert(TK_GE==OP_Ge); testcase(op==OP_Ge); VdbeCoverageIf(v,op==OP_Ge);
+      assert(TK_EQ==OP_Eq); testcase(op==OP_Eq);
+      VdbeCoverageIf(v, op==OP_Eq && jumpIfNull==SQLITE_NULLEQ);
+      VdbeCoverageIf(v, op==OP_Eq && jumpIfNull!=SQLITE_NULLEQ);
+      assert(TK_NE==OP_Ne); testcase(op==OP_Ne);
+      VdbeCoverageIf(v, op==OP_Ne && jumpIfNull==SQLITE_NULLEQ);
+      VdbeCoverageIf(v, op==OP_Ne && jumpIfNull!=SQLITE_NULLEQ);
+      testcase( regFree1==0 );
+      testcase( regFree2==0 );
+      break;
+    }
+    case TK_ISNULL:
+    case TK_NOTNULL: {
+      assert( TK_ISNULL==OP_IsNull );   testcase( op==TK_ISNULL );
+      assert( TK_NOTNULL==OP_NotNull ); testcase( op==TK_NOTNULL );
+      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
+      sqlite3VdbeAddOp2(v, op, r1, dest);
+      VdbeCoverageIf(v, op==TK_ISNULL);
+      VdbeCoverageIf(v, op==TK_NOTNULL);
+      testcase( regFree1==0 );
+      break;
+    }
+    case TK_BETWEEN: {
+      testcase( jumpIfNull==0 );
+      exprCodeBetween(pParse, pExpr, dest, sqlite3ExprIfTrue, jumpIfNull);
+      break;
+    }
+#ifndef SQLITE_OMIT_SUBQUERY
+    case TK_IN: {
+      int destIfFalse = sqlite3VdbeMakeLabel(v);
+      int destIfNull = jumpIfNull ? dest : destIfFalse;
+      sqlite3ExprCodeIN(pParse, pExpr, destIfFalse, destIfNull);
+      sqlite3VdbeGoto(v, dest);
+      sqlite3VdbeResolveLabel(v, destIfFalse);
+      break;
+    }
+#endif
+    default: {
+    default_expr:
+      if( exprAlwaysTrue(pExpr) ){
+        sqlite3VdbeGoto(v, dest);
+      }else if( exprAlwaysFalse(pExpr) ){
+        /* No-op */
+      }else{
+        r1 = sqlite3ExprCodeTemp(pParse, pExpr, &regFree1);
+        sqlite3VdbeAddOp3(v, OP_If, r1, dest, jumpIfNull!=0);
+        VdbeCoverage(v);
+        testcase( regFree1==0 );
+        testcase( jumpIfNull==0 );
+      }
+      break;
+    }
+  }
+  sqlite3ReleaseTempReg(pParse, regFree1);
+  sqlite3ReleaseTempReg(pParse, regFree2);  
+}
+
+/*
+** Generate code for a boolean expression such that a jump is made
+** to the label "dest" if the expression is false but execution
+** continues straight thru if the expression is true.
+**
+** If the expression evaluates to NULL (neither true nor false) then
+** jump if jumpIfNull is SQLITE_JUMPIFNULL or fall through if jumpIfNull
+** is 0.
+*/
+void sqlite3ExprIfFalse(Parse *pParse, Expr *pExpr, int dest, int jumpIfNull){
+  Vdbe *v = pParse->pVdbe;
+  int op = 0;
+  int regFree1 = 0;
+  int regFree2 = 0;
+  int r1, r2;
+
+  assert( jumpIfNull==SQLITE_JUMPIFNULL || jumpIfNull==0 );
+  if( NEVER(v==0) ) return; /* Existence of VDBE checked by caller */
+  if( pExpr==0 )    return;
+
+  /* The value of pExpr->op and op are related as follows:
+  **
+  **       pExpr->op            op
+  **       ---------          ----------
+  **       TK_ISNULL          OP_NotNull
+  **       TK_NOTNULL         OP_IsNull
+  **       TK_NE              OP_Eq
+  **       TK_EQ              OP_Ne
+  **       TK_GT              OP_Le
+  **       TK_LE              OP_Gt
+  **       TK_GE              OP_Lt
+  **       TK_LT              OP_Ge
+  **
+  ** For other values of pExpr->op, op is undefined and unused.
+  ** The value of TK_ and OP_ constants are arranged such that we
+  ** can compute the mapping above using the following expression.
+  ** Assert()s verify that the computation is correct.
+  */
+  op = ((pExpr->op+(TK_ISNULL&1))^1)-(TK_ISNULL&1);
+
+  /* Verify correct alignment of TK_ and OP_ constants
+  */
+  assert( pExpr->op!=TK_ISNULL || op==OP_NotNull );
+  assert( pExpr->op!=TK_NOTNULL || op==OP_IsNull );
+  assert( pExpr->op!=TK_NE || op==OP_Eq );
+  assert( pExpr->op!=TK_EQ || op==OP_Ne );
+  assert( pExpr->op!=TK_LT || op==OP_Ge );
+  assert( pExpr->op!=TK_LE || op==OP_Gt );
+  assert( pExpr->op!=TK_GT || op==OP_Le );
+  assert( pExpr->op!=TK_GE || op==OP_Lt );
+
+  switch( pExpr->op ){
+    case TK_AND: {
+      testcase( jumpIfNull==0 );
+      sqlite3ExprIfFalse(pParse, pExpr->pLeft, dest, jumpIfNull);
+      sqlite3ExprCachePush(pParse);
+      sqlite3ExprIfFalse(pParse, pExpr->pRight, dest, jumpIfNull);
+      sqlite3ExprCachePop(pParse);
+      break;
+    }
+    case TK_OR: {
+      int d2 = sqlite3VdbeMakeLabel(v);
+      testcase( jumpIfNull==0 );
+      sqlite3ExprIfTrue(pParse, pExpr->pLeft, d2, jumpIfNull^SQLITE_JUMPIFNULL);
+      sqlite3ExprCachePush(pParse);
+      sqlite3ExprIfFalse(pParse, pExpr->pRight, dest, jumpIfNull);
+      sqlite3VdbeResolveLabel(v, d2);
+      sqlite3ExprCachePop(pParse);
+      break;
+    }
+    case TK_NOT: {
+      testcase( jumpIfNull==0 );
+      sqlite3ExprIfTrue(pParse, pExpr->pLeft, dest, jumpIfNull);
+      break;
+    }
+    case TK_IS:
+    case TK_ISNOT:
+      testcase( pExpr->op==TK_IS );
+      testcase( pExpr->op==TK_ISNOT );
+      op = (pExpr->op==TK_IS) ? TK_NE : TK_EQ;
+      jumpIfNull = SQLITE_NULLEQ;
+      /* Fall thru */
+    case TK_LT:
+    case TK_LE:
+    case TK_GT:
+    case TK_GE:
+    case TK_NE:
+    case TK_EQ: {
+      if( sqlite3ExprIsVector(pExpr->pLeft) ) goto default_expr;
+      testcase( jumpIfNull==0 );
+      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
+      r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, &regFree2);
+      codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op,
+                  r1, r2, dest, jumpIfNull);
+      assert(TK_LT==OP_Lt); testcase(op==OP_Lt); VdbeCoverageIf(v,op==OP_Lt);
+      assert(TK_LE==OP_Le); testcase(op==OP_Le); VdbeCoverageIf(v,op==OP_Le);
+      assert(TK_GT==OP_Gt); testcase(op==OP_Gt); VdbeCoverageIf(v,op==OP_Gt);
+      assert(TK_GE==OP_Ge); testcase(op==OP_Ge); VdbeCoverageIf(v,op==OP_Ge);
+      assert(TK_EQ==OP_Eq); testcase(op==OP_Eq);
+      VdbeCoverageIf(v, op==OP_Eq && jumpIfNull!=SQLITE_NULLEQ);
+      VdbeCoverageIf(v, op==OP_Eq && jumpIfNull==SQLITE_NULLEQ);
+      assert(TK_NE==OP_Ne); testcase(op==OP_Ne);
+      VdbeCoverageIf(v, op==OP_Ne && jumpIfNull!=SQLITE_NULLEQ);
+      VdbeCoverageIf(v, op==OP_Ne && jumpIfNull==SQLITE_NULLEQ);
+      testcase( regFree1==0 );
+      testcase( regFree2==0 );
+      break;
+    }
+    case TK_ISNULL:
+    case TK_NOTNULL: {
+      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
+      sqlite3VdbeAddOp2(v, op, r1, dest);
+      testcase( op==TK_ISNULL );   VdbeCoverageIf(v, op==TK_ISNULL);
+      testcase( op==TK_NOTNULL );  VdbeCoverageIf(v, op==TK_NOTNULL);
+      testcase( regFree1==0 );
+      break;
+    }
+    case TK_BETWEEN: {
+      testcase( jumpIfNull==0 );
+      exprCodeBetween(pParse, pExpr, dest, sqlite3ExprIfFalse, jumpIfNull);
+      break;
+    }
+#ifndef SQLITE_OMIT_SUBQUERY
+    case TK_IN: {
+      if( jumpIfNull ){
+        sqlite3ExprCodeIN(pParse, pExpr, dest, dest);
+      }else{
+        int destIfNull = sqlite3VdbeMakeLabel(v);
+        sqlite3ExprCodeIN(pParse, pExpr, dest, destIfNull);
+        sqlite3VdbeResolveLabel(v, destIfNull);
+      }
+      break;
+    }
+#endif
+    default: {
+    default_expr: 
+      if( exprAlwaysFalse(pExpr) ){
+        sqlite3VdbeGoto(v, dest);
+      }else if( exprAlwaysTrue(pExpr) ){
+        /* no-op */
+      }else{
+        r1 = sqlite3ExprCodeTemp(pParse, pExpr, &regFree1);
+        sqlite3VdbeAddOp3(v, OP_IfNot, r1, dest, jumpIfNull!=0);
+        VdbeCoverage(v);
+        testcase( regFree1==0 );
+        testcase( jumpIfNull==0 );
+      }
+      break;
+    }
+  }
+  sqlite3ReleaseTempReg(pParse, regFree1);
+  sqlite3ReleaseTempReg(pParse, regFree2);
+}
+
+/*
+** Like sqlite3ExprIfFalse() except that a copy is made of pExpr before
+** code generation, and that copy is deleted after code generation. This
+** ensures that the original pExpr is unchanged.
+*/
+void sqlite3ExprIfFalseDup(Parse *pParse, Expr *pExpr, int dest,int jumpIfNull){
+  sqlite3 *db = pParse->db;
+  Expr *pCopy = sqlite3ExprDup(db, pExpr, 0);
+  if( db->mallocFailed==0 ){
+    sqlite3ExprIfFalse(pParse, pCopy, dest, jumpIfNull);
+  }
+  sqlite3ExprDelete(db, pCopy);
+}
+
+
+/*
+** Do a deep comparison of two expression trees.  Return 0 if the two
+** expressions are completely identical.  Return 1 if they differ only
+** by a COLLATE operator at the top level.  Return 2 if there are differences
+** other than the top-level COLLATE operator.
+**
+** If any subelement of pB has Expr.iTable==(-1) then it is allowed
+** to compare equal to an equivalent element in pA with Expr.iTable==iTab.
+**
+** The pA side might be using TK_REGISTER.  If that is the case and pB is
+** not using TK_REGISTER but is otherwise equivalent, then still return 0.
+**
+** Sometimes this routine will return 2 even if the two expressions
+** really are equivalent.  If we cannot prove that the expressions are
+** identical, we return 2 just to be safe.  So if this routine
+** returns 2, then you do not really know for certain if the two
+** expressions are the same.  But if you get a 0 or 1 return, then you
+** can be sure the expressions are the same.  In the places where
+** this routine is used, it does not hurt to get an extra 2 - that
+** just might result in some slightly slower code.  But returning
+** an incorrect 0 or 1 could lead to a malfunction.
+*/
+int sqlite3ExprCompare(Expr *pA, Expr *pB, int iTab){
+  u32 combinedFlags;
+  if( pA==0 || pB==0 ){
+    return pB==pA ? 0 : 2;
+  }
+  combinedFlags = pA->flags | pB->flags;
+  if( combinedFlags & EP_IntValue ){
+    if( (pA->flags&pB->flags&EP_IntValue)!=0 && pA->u.iValue==pB->u.iValue ){
+      return 0;
+    }
+    return 2;
+  }
+  if( pA->op!=pB->op ){
+    if( pA->op==TK_COLLATE && sqlite3ExprCompare(pA->pLeft, pB, iTab)<2 ){
+      return 1;
+    }
+    if( pB->op==TK_COLLATE && sqlite3ExprCompare(pA, pB->pLeft, iTab)<2 ){
+      return 1;
+    }
+    return 2;
+  }
+  if( pA->op!=TK_COLUMN && pA->op!=TK_AGG_COLUMN && pA->u.zToken ){
+    if( pA->op==TK_FUNCTION ){
+      if( sqlite3StrICmp(pA->u.zToken,pB->u.zToken)!=0 ) return 2;
+    }else if( strcmp(pA->u.zToken,pB->u.zToken)!=0 ){
+      return pA->op==TK_COLLATE ? 1 : 2;
+    }
+  }
+  if( (pA->flags & EP_Distinct)!=(pB->flags & EP_Distinct) ) return 2;
+  if( ALWAYS((combinedFlags & EP_TokenOnly)==0) ){
+    if( combinedFlags & EP_xIsSelect ) return 2;
+    if( sqlite3ExprCompare(pA->pLeft, pB->pLeft, iTab) ) return 2;
+    if( sqlite3ExprCompare(pA->pRight, pB->pRight, iTab) ) return 2;
+    if( sqlite3ExprListCompare(pA->x.pList, pB->x.pList, iTab) ) return 2;
+    if( ALWAYS((combinedFlags & EP_Reduced)==0) && pA->op!=TK_STRING ){
+      if( pA->iColumn!=pB->iColumn ) return 2;
+      if( pA->iTable!=pB->iTable 
+       && (pA->iTable!=iTab || NEVER(pB->iTable>=0)) ) return 2;
+    }
+  }
+  return 0;
+}
+
+/*
+** Compare two ExprList objects.  Return 0 if they are identical and 
+** non-zero if they differ in any way.
+**
+** If any subelement of pB has Expr.iTable==(-1) then it is allowed
+** to compare equal to an equivalent element in pA with Expr.iTable==iTab.
+**
+** This routine might return non-zero for equivalent ExprLists.  The
+** only consequence will be disabled optimizations.  But this routine
+** must never return 0 if the two ExprList objects are different, or
+** a malfunction will result.
+**
+** Two NULL pointers are considered to be the same.  But a NULL pointer
+** always differs from a non-NULL pointer.
+*/
+int sqlite3ExprListCompare(ExprList *pA, ExprList *pB, int iTab){
+  int i;
+  if( pA==0 && pB==0 ) return 0;
+  if( pA==0 || pB==0 ) return 1;
+  if( pA->nExpr!=pB->nExpr ) return 1;
+  for(i=0; i<pA->nExpr; i++){
+    Expr *pExprA = pA->a[i].pExpr;
+    Expr *pExprB = pB->a[i].pExpr;
+    if( pA->a[i].sortOrder!=pB->a[i].sortOrder ) return 1;
+    if( sqlite3ExprCompare(pExprA, pExprB, iTab) ) return 1;
+  }
+  return 0;
+}
+
+/*
+** Return true if we can prove the pE2 will always be true if pE1 is
+** true.  Return false if we cannot complete the proof or if pE2 might
+** be false.  Examples:
+**
+**     pE1: x==5       pE2: x==5             Result: true
+**     pE1: x>0        pE2: x==5             Result: false
+**     pE1: x=21       pE2: x=21 OR y=43     Result: true
+**     pE1: x!=123     pE2: x IS NOT NULL    Result: true
+**     pE1: x!=?1      pE2: x IS NOT NULL    Result: true
+**     pE1: x IS NULL  pE2: x IS NOT NULL    Result: false
+**     pE1: x IS ?2    pE2: x IS NOT NULL    Reuslt: false
+**
+** When comparing TK_COLUMN nodes between pE1 and pE2, if pE2 has
+** Expr.iTable<0 then assume a table number given by iTab.
+**
+** When in doubt, return false.  Returning true might give a performance
+** improvement.  Returning false might cause a performance reduction, but
+** it will always give the correct answer and is hence always safe.
+*/
+int sqlite3ExprImpliesExpr(Expr *pE1, Expr *pE2, int iTab){
+  if( sqlite3ExprCompare(pE1, pE2, iTab)==0 ){
+    return 1;
+  }
+  if( pE2->op==TK_OR
+   && (sqlite3ExprImpliesExpr(pE1, pE2->pLeft, iTab)
+             || sqlite3ExprImpliesExpr(pE1, pE2->pRight, iTab) )
+  ){
+    return 1;
+  }
+  if( pE2->op==TK_NOTNULL && pE1->op!=TK_ISNULL && pE1->op!=TK_IS ){
+    Expr *pX = sqlite3ExprSkipCollate(pE1->pLeft);
+    testcase( pX!=pE1->pLeft );
+    if( sqlite3ExprCompare(pX, pE2->pLeft, iTab)==0 ) return 1;
+  }
+  return 0;
+}
+
+/*
+** An instance of the following structure is used by the tree walker
+** to determine if an expression can be evaluated by reference to the
+** index only, without having to do a search for the corresponding
+** table entry.  The IdxCover.pIdx field is the index.  IdxCover.iCur
+** is the cursor for the table.
+*/
+struct IdxCover {
+  Index *pIdx;     /* The index to be tested for coverage */
+  int iCur;        /* Cursor number for the table corresponding to the index */
+};
+
+/*
+** Check to see if there are references to columns in table 
+** pWalker->u.pIdxCover->iCur can be satisfied using the index
+** pWalker->u.pIdxCover->pIdx.
+*/
+static int exprIdxCover(Walker *pWalker, Expr *pExpr){
+  if( pExpr->op==TK_COLUMN
+   && pExpr->iTable==pWalker->u.pIdxCover->iCur
+   && sqlite3ColumnOfIndex(pWalker->u.pIdxCover->pIdx, pExpr->iColumn)<0
+  ){
+    pWalker->eCode = 1;
+    return WRC_Abort;
+  }
+  return WRC_Continue;
+}
+
+/*
+** Determine if an index pIdx on table with cursor iCur contains will
+** the expression pExpr.  Return true if the index does cover the
+** expression and false if the pExpr expression references table columns
+** that are not found in the index pIdx.
+**
+** An index covering an expression means that the expression can be
+** evaluated using only the index and without having to lookup the
+** corresponding table entry.
+*/
+int sqlite3ExprCoveredByIndex(
+  Expr *pExpr,        /* The index to be tested */
+  int iCur,           /* The cursor number for the corresponding table */
+  Index *pIdx         /* The index that might be used for coverage */
+){
+  Walker w;
+  struct IdxCover xcov;
+  memset(&w, 0, sizeof(w));
+  xcov.iCur = iCur;
+  xcov.pIdx = pIdx;
+  w.xExprCallback = exprIdxCover;
+  w.u.pIdxCover = &xcov;
+  sqlite3WalkExpr(&w, pExpr);
+  return !w.eCode;
+}
+
+
+/*
+** An instance of the following structure is used by the tree walker
+** to count references to table columns in the arguments of an 
+** aggregate function, in order to implement the
+** sqlite3FunctionThisSrc() routine.
+*/
+struct SrcCount {
+  SrcList *pSrc;   /* One particular FROM clause in a nested query */
+  int nThis;       /* Number of references to columns in pSrcList */
+  int nOther;      /* Number of references to columns in other FROM clauses */
+};
+
+/*
+** Count the number of references to columns.
+*/
+static int exprSrcCount(Walker *pWalker, Expr *pExpr){
+  /* The NEVER() on the second term is because sqlite3FunctionUsesThisSrc()
+  ** is always called before sqlite3ExprAnalyzeAggregates() and so the
+  ** TK_COLUMNs have not yet been converted into TK_AGG_COLUMN.  If
+  ** sqlite3FunctionUsesThisSrc() is used differently in the future, the
+  ** NEVER() will need to be removed. */
+  if( pExpr->op==TK_COLUMN || NEVER(pExpr->op==TK_AGG_COLUMN) ){
+    int i;
+    struct SrcCount *p = pWalker->u.pSrcCount;
+    SrcList *pSrc = p->pSrc;
+    int nSrc = pSrc ? pSrc->nSrc : 0;
+    for(i=0; i<nSrc; i++){
+      if( pExpr->iTable==pSrc->a[i].iCursor ) break;
+    }
+    if( i<nSrc ){
+      p->nThis++;
+    }else{
+      p->nOther++;
+    }
+  }
+  return WRC_Continue;
+}
+
+/*
+** Determine if any of the arguments to the pExpr Function reference
+** pSrcList.  Return true if they do.  Also return true if the function
+** has no arguments or has only constant arguments.  Return false if pExpr
+** references columns but not columns of tables found in pSrcList.
+*/
+int sqlite3FunctionUsesThisSrc(Expr *pExpr, SrcList *pSrcList){
+  Walker w;
+  struct SrcCount cnt;
+  assert( pExpr->op==TK_AGG_FUNCTION );
+  memset(&w, 0, sizeof(w));
+  w.xExprCallback = exprSrcCount;
+  w.u.pSrcCount = &cnt;
+  cnt.pSrc = pSrcList;
+  cnt.nThis = 0;
+  cnt.nOther = 0;
+  sqlite3WalkExprList(&w, pExpr->x.pList);
+  return cnt.nThis>0 || cnt.nOther==0;
+}
+
+/*
+** Add a new element to the pAggInfo->aCol[] array.  Return the index of
+** the new element.  Return a negative number if malloc fails.
+*/
+static int addAggInfoColumn(sqlite3 *db, AggInfo *pInfo){
+  int i;
+  pInfo->aCol = sqlite3ArrayAllocate(
+       db,
+       pInfo->aCol,
+       sizeof(pInfo->aCol[0]),
+       &pInfo->nColumn,
+       &i
+  );
+  return i;
+}    
+
+/*
+** Add a new element to the pAggInfo->aFunc[] array.  Return the index of
+** the new element.  Return a negative number if malloc fails.
+*/
+static int addAggInfoFunc(sqlite3 *db, AggInfo *pInfo){
+  int i;
+  pInfo->aFunc = sqlite3ArrayAllocate(
+       db, 
+       pInfo->aFunc,
+       sizeof(pInfo->aFunc[0]),
+       &pInfo->nFunc,
+       &i
+  );
+  return i;
+}    
+
+/*
+** This is the xExprCallback for a tree walker.  It is used to
+** implement sqlite3ExprAnalyzeAggregates().  See sqlite3ExprAnalyzeAggregates
+** for additional information.
+*/
+static int analyzeAggregate(Walker *pWalker, Expr *pExpr){
+  int i;
+  NameContext *pNC = pWalker->u.pNC;
+  Parse *pParse = pNC->pParse;
+  SrcList *pSrcList = pNC->pSrcList;
+  AggInfo *pAggInfo = pNC->pAggInfo;
+
+  switch( pExpr->op ){
+    case TK_AGG_COLUMN:
+    case TK_COLUMN: {
+      testcase( pExpr->op==TK_AGG_COLUMN );
+      testcase( pExpr->op==TK_COLUMN );
+      /* Check to see if the column is in one of the tables in the FROM
+      ** clause of the aggregate query */
+      if( ALWAYS(pSrcList!=0) ){
+        struct SrcList_item *pItem = pSrcList->a;
+        for(i=0; i<pSrcList->nSrc; i++, pItem++){
+          struct AggInfo_col *pCol;
+          assert( !ExprHasProperty(pExpr, EP_TokenOnly|EP_Reduced) );
+          if( pExpr->iTable==pItem->iCursor ){
+            /* If we reach this point, it means that pExpr refers to a table
+            ** that is in the FROM clause of the aggregate query.  
+            **
+            ** Make an entry for the column in pAggInfo->aCol[] if there
+            ** is not an entry there already.
+            */
+            int k;
+            pCol = pAggInfo->aCol;
+            for(k=0; k<pAggInfo->nColumn; k++, pCol++){
+              if( pCol->iTable==pExpr->iTable &&
+                  pCol->iColumn==pExpr->iColumn ){
+                break;
+              }
+            }
+            if( (k>=pAggInfo->nColumn)
+             && (k = addAggInfoColumn(pParse->db, pAggInfo))>=0 
+            ){
+              pCol = &pAggInfo->aCol[k];
+              pCol->pTab = pExpr->pTab;
+              pCol->iTable = pExpr->iTable;
+              pCol->iColumn = pExpr->iColumn;
+              pCol->iMem = ++pParse->nMem;
+              pCol->iSorterColumn = -1;
+              pCol->pExpr = pExpr;
+              if( pAggInfo->pGroupBy ){
+                int j, n;
+                ExprList *pGB = pAggInfo->pGroupBy;
+                struct ExprList_item *pTerm = pGB->a;
+                n = pGB->nExpr;
+                for(j=0; j<n; j++, pTerm++){
+                  Expr *pE = pTerm->pExpr;
+                  if( pE->op==TK_COLUMN && pE->iTable==pExpr->iTable &&
+                      pE->iColumn==pExpr->iColumn ){
+                    pCol->iSorterColumn = j;
+                    break;
+                  }
+                }
+              }
+              if( pCol->iSorterColumn<0 ){
+                pCol->iSorterColumn = pAggInfo->nSortingColumn++;
+              }
+            }
+            /* There is now an entry for pExpr in pAggInfo->aCol[] (either
+            ** because it was there before or because we just created it).
+            ** Convert the pExpr to be a TK_AGG_COLUMN referring to that
+            ** pAggInfo->aCol[] entry.
+            */
+            ExprSetVVAProperty(pExpr, EP_NoReduce);
+            pExpr->pAggInfo = pAggInfo;
+            pExpr->op = TK_AGG_COLUMN;
+            pExpr->iAgg = (i16)k;
+            break;
+          } /* endif pExpr->iTable==pItem->iCursor */
+        } /* end loop over pSrcList */
+      }
+      return WRC_Prune;
+    }
+    case TK_AGG_FUNCTION: {
+      if( (pNC->ncFlags & NC_InAggFunc)==0
+       && pWalker->walkerDepth==pExpr->op2
+      ){
+        /* Check to see if pExpr is a duplicate of another aggregate 
+        ** function that is already in the pAggInfo structure
+        */
+        struct AggInfo_func *pItem = pAggInfo->aFunc;
+        for(i=0; i<pAggInfo->nFunc; i++, pItem++){
+          if( sqlite3ExprCompare(pItem->pExpr, pExpr, -1)==0 ){
+            break;
+          }
+        }
+        if( i>=pAggInfo->nFunc ){
+          /* pExpr is original.  Make a new entry in pAggInfo->aFunc[]
+          */
+          u8 enc = ENC(pParse->db);
+          i = addAggInfoFunc(pParse->db, pAggInfo);
+          if( i>=0 ){
+            assert( !ExprHasProperty(pExpr, EP_xIsSelect) );
+            pItem = &pAggInfo->aFunc[i];
+            pItem->pExpr = pExpr;
+            pItem->iMem = ++pParse->nMem;
+            assert( !ExprHasProperty(pExpr, EP_IntValue) );
+            pItem->pFunc = sqlite3FindFunction(pParse->db,
+                   pExpr->u.zToken, 
+                   pExpr->x.pList ? pExpr->x.pList->nExpr : 0, enc, 0);
+            if( pExpr->flags & EP_Distinct ){
+              pItem->iDistinct = pParse->nTab++;
+            }else{
+              pItem->iDistinct = -1;
+            }
+          }
+        }
+        /* Make pExpr point to the appropriate pAggInfo->aFunc[] entry
+        */
+        assert( !ExprHasProperty(pExpr, EP_TokenOnly|EP_Reduced) );
+        ExprSetVVAProperty(pExpr, EP_NoReduce);
+        pExpr->iAgg = (i16)i;
+        pExpr->pAggInfo = pAggInfo;
+        return WRC_Prune;
+      }else{
+        return WRC_Continue;
+      }
+    }
+  }
+  return WRC_Continue;
+}
+static int analyzeAggregatesInSelect(Walker *pWalker, Select *pSelect){
+  UNUSED_PARAMETER(pWalker);
+  UNUSED_PARAMETER(pSelect);
+  return WRC_Continue;
+}
+
+/*
+** Analyze the pExpr expression looking for aggregate functions and
+** for variables that need to be added to AggInfo object that pNC->pAggInfo
+** points to.  Additional entries are made on the AggInfo object as
+** necessary.
+**
+** This routine should only be called after the expression has been
+** analyzed by sqlite3ResolveExprNames().
+*/
+void sqlite3ExprAnalyzeAggregates(NameContext *pNC, Expr *pExpr){
+  Walker w;
+  memset(&w, 0, sizeof(w));
+  w.xExprCallback = analyzeAggregate;
+  w.xSelectCallback = analyzeAggregatesInSelect;
+  w.u.pNC = pNC;
+  assert( pNC->pSrcList!=0 );
+  sqlite3WalkExpr(&w, pExpr);
+}
+
+/*
+** Call sqlite3ExprAnalyzeAggregates() for every expression in an
+** expression list.  Return the number of errors.
+**
+** If an error is found, the analysis is cut short.
+*/
+void sqlite3ExprAnalyzeAggList(NameContext *pNC, ExprList *pList){
+  struct ExprList_item *pItem;
+  int i;
+  if( pList ){
+    for(pItem=pList->a, i=0; i<pList->nExpr; i++, pItem++){
+      sqlite3ExprAnalyzeAggregates(pNC, pItem->pExpr);
+    }
+  }
+}
+
+/*
+** Allocate a single new register for use to hold some intermediate result.
+*/
+int sqlite3GetTempReg(Parse *pParse){
+  if( pParse->nTempReg==0 ){
+    return ++pParse->nMem;
+  }
+  return pParse->aTempReg[--pParse->nTempReg];
+}
+
+/*
+** Deallocate a register, making available for reuse for some other
+** purpose.
+**
+** If a register is currently being used by the column cache, then
+** the deallocation is deferred until the column cache line that uses
+** the register becomes stale.
+*/
+void sqlite3ReleaseTempReg(Parse *pParse, int iReg){
+  if( iReg && pParse->nTempReg<ArraySize(pParse->aTempReg) ){
+    int i;
+    struct yColCache *p;
+    for(i=0, p=pParse->aColCache; i<pParse->nColCache; i++, p++){
+      if( p->iReg==iReg ){
+        p->tempReg = 1;
+        return;
+      }
+    }
+    pParse->aTempReg[pParse->nTempReg++] = iReg;
+  }
+}
+
+/*
+** Allocate or deallocate a block of nReg consecutive registers.
+*/
+int sqlite3GetTempRange(Parse *pParse, int nReg){
+  int i, n;
+  if( nReg==1 ) return sqlite3GetTempReg(pParse);
+  i = pParse->iRangeReg;
+  n = pParse->nRangeReg;
+  if( nReg<=n ){
+    assert( !usedAsColumnCache(pParse, i, i+n-1) );
+    pParse->iRangeReg += nReg;
+    pParse->nRangeReg -= nReg;
+  }else{
+    i = pParse->nMem+1;
+    pParse->nMem += nReg;
+  }
+  return i;
+}
+void sqlite3ReleaseTempRange(Parse *pParse, int iReg, int nReg){
+  if( nReg==1 ){
+    sqlite3ReleaseTempReg(pParse, iReg);
+    return;
+  }
+  sqlite3ExprCacheRemove(pParse, iReg, nReg);
+  if( nReg>pParse->nRangeReg ){
+    pParse->nRangeReg = nReg;
+    pParse->iRangeReg = iReg;
+  }
+}
+
+/*
+** Mark all temporary registers as being unavailable for reuse.
+*/
+void sqlite3ClearTempRegCache(Parse *pParse){
+  pParse->nTempReg = 0;
+  pParse->nRangeReg = 0;
+}
+
+/*
+** Validate that no temporary register falls within the range of
+** iFirst..iLast, inclusive.  This routine is only call from within assert()
+** statements.
+*/
+#ifdef SQLITE_DEBUG
+int sqlite3NoTempsInRange(Parse *pParse, int iFirst, int iLast){
+  int i;
+  if( pParse->nRangeReg>0
+   && pParse->iRangeReg+pParse->nRangeReg<iLast
+   && pParse->iRangeReg>=iFirst
+  ){
+     return 0;
+  }
+  for(i=0; i<pParse->nTempReg; i++){
+    if( pParse->aTempReg[i]>=iFirst && pParse->aTempReg[i]<=iLast ){
+      return 0;
+    }
+  }
+  return 1;
+}
+#endif /* SQLITE_DEBUG */