| Index: third_party/sqlite/src/src/select.c
|
| diff --git a/third_party/sqlite/src/src/select.c b/third_party/sqlite/src/src/select.c
|
| new file mode 100644
|
| index 0000000000000000000000000000000000000000..3a4a8816847eae89f5de4f3ac9db9975da4503a7
|
| --- /dev/null
|
| +++ b/third_party/sqlite/src/src/select.c
|
| @@ -0,0 +1,4465 @@
|
| +/*
|
| +** 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 C code routines that are called by the parser
|
| +** to handle SELECT statements in SQLite.
|
| +*/
|
| +#include "sqliteInt.h"
|
| +
|
| +
|
| +/*
|
| +** Delete all the content of a Select structure but do not deallocate
|
| +** the select structure itself.
|
| +*/
|
| +static void clearSelect(sqlite3 *db, Select *p){
|
| + sqlite3ExprListDelete(db, p->pEList);
|
| + sqlite3SrcListDelete(db, p->pSrc);
|
| + sqlite3ExprDelete(db, p->pWhere);
|
| + sqlite3ExprListDelete(db, p->pGroupBy);
|
| + sqlite3ExprDelete(db, p->pHaving);
|
| + sqlite3ExprListDelete(db, p->pOrderBy);
|
| + sqlite3SelectDelete(db, p->pPrior);
|
| + sqlite3ExprDelete(db, p->pLimit);
|
| + sqlite3ExprDelete(db, p->pOffset);
|
| +}
|
| +
|
| +/*
|
| +** Initialize a SelectDest structure.
|
| +*/
|
| +void sqlite3SelectDestInit(SelectDest *pDest, int eDest, int iParm){
|
| + pDest->eDest = (u8)eDest;
|
| + pDest->iParm = iParm;
|
| + pDest->affinity = 0;
|
| + pDest->iMem = 0;
|
| + pDest->nMem = 0;
|
| +}
|
| +
|
| +
|
| +/*
|
| +** Allocate a new Select structure and return a pointer to that
|
| +** structure.
|
| +*/
|
| +Select *sqlite3SelectNew(
|
| + Parse *pParse, /* Parsing context */
|
| + ExprList *pEList, /* which columns to include in the result */
|
| + SrcList *pSrc, /* the FROM clause -- which tables to scan */
|
| + Expr *pWhere, /* the WHERE clause */
|
| + ExprList *pGroupBy, /* the GROUP BY clause */
|
| + Expr *pHaving, /* the HAVING clause */
|
| + ExprList *pOrderBy, /* the ORDER BY clause */
|
| + int isDistinct, /* true if the DISTINCT keyword is present */
|
| + Expr *pLimit, /* LIMIT value. NULL means not used */
|
| + Expr *pOffset /* OFFSET value. NULL means no offset */
|
| +){
|
| + Select *pNew;
|
| + Select standin;
|
| + sqlite3 *db = pParse->db;
|
| + pNew = sqlite3DbMallocZero(db, sizeof(*pNew) );
|
| + assert( db->mallocFailed || !pOffset || pLimit ); /* OFFSET implies LIMIT */
|
| + if( pNew==0 ){
|
| + pNew = &standin;
|
| + memset(pNew, 0, sizeof(*pNew));
|
| + }
|
| + if( pEList==0 ){
|
| + pEList = sqlite3ExprListAppend(pParse, 0, sqlite3Expr(db,TK_ALL,0));
|
| + }
|
| + pNew->pEList = pEList;
|
| + pNew->pSrc = pSrc;
|
| + pNew->pWhere = pWhere;
|
| + pNew->pGroupBy = pGroupBy;
|
| + pNew->pHaving = pHaving;
|
| + pNew->pOrderBy = pOrderBy;
|
| + pNew->selFlags = isDistinct ? SF_Distinct : 0;
|
| + pNew->op = TK_SELECT;
|
| + pNew->pLimit = pLimit;
|
| + pNew->pOffset = pOffset;
|
| + assert( pOffset==0 || pLimit!=0 );
|
| + pNew->addrOpenEphm[0] = -1;
|
| + pNew->addrOpenEphm[1] = -1;
|
| + pNew->addrOpenEphm[2] = -1;
|
| + if( db->mallocFailed ) {
|
| + clearSelect(db, pNew);
|
| + if( pNew!=&standin ) sqlite3DbFree(db, pNew);
|
| + pNew = 0;
|
| + }
|
| + return pNew;
|
| +}
|
| +
|
| +/*
|
| +** Delete the given Select structure and all of its substructures.
|
| +*/
|
| +void sqlite3SelectDelete(sqlite3 *db, Select *p){
|
| + if( p ){
|
| + clearSelect(db, p);
|
| + sqlite3DbFree(db, p);
|
| + }
|
| +}
|
| +
|
| +/*
|
| +** Given 1 to 3 identifiers preceeding the JOIN keyword, determine the
|
| +** type of join. Return an integer constant that expresses that type
|
| +** in terms of the following bit values:
|
| +**
|
| +** JT_INNER
|
| +** JT_CROSS
|
| +** JT_OUTER
|
| +** JT_NATURAL
|
| +** JT_LEFT
|
| +** JT_RIGHT
|
| +**
|
| +** A full outer join is the combination of JT_LEFT and JT_RIGHT.
|
| +**
|
| +** If an illegal or unsupported join type is seen, then still return
|
| +** a join type, but put an error in the pParse structure.
|
| +*/
|
| +int sqlite3JoinType(Parse *pParse, Token *pA, Token *pB, Token *pC){
|
| + int jointype = 0;
|
| + Token *apAll[3];
|
| + Token *p;
|
| + /* 0123456789 123456789 123456789 123 */
|
| + static const char zKeyText[] = "naturaleftouterightfullinnercross";
|
| + static const struct {
|
| + u8 i; /* Beginning of keyword text in zKeyText[] */
|
| + u8 nChar; /* Length of the keyword in characters */
|
| + u8 code; /* Join type mask */
|
| + } aKeyword[] = {
|
| + /* natural */ { 0, 7, JT_NATURAL },
|
| + /* left */ { 6, 4, JT_LEFT|JT_OUTER },
|
| + /* outer */ { 10, 5, JT_OUTER },
|
| + /* right */ { 14, 5, JT_RIGHT|JT_OUTER },
|
| + /* full */ { 19, 4, JT_LEFT|JT_RIGHT|JT_OUTER },
|
| + /* inner */ { 23, 5, JT_INNER },
|
| + /* cross */ { 28, 5, JT_INNER|JT_CROSS },
|
| + };
|
| + int i, j;
|
| + apAll[0] = pA;
|
| + apAll[1] = pB;
|
| + apAll[2] = pC;
|
| + for(i=0; i<3 && apAll[i]; i++){
|
| + p = apAll[i];
|
| + for(j=0; j<ArraySize(aKeyword); j++){
|
| + if( p->n==aKeyword[j].nChar
|
| + && sqlite3StrNICmp((char*)p->z, &zKeyText[aKeyword[j].i], p->n)==0 ){
|
| + jointype |= aKeyword[j].code;
|
| + break;
|
| + }
|
| + }
|
| + testcase( j==0 || j==1 || j==2 || j==3 || j==4 || j==5 || j==6 );
|
| + if( j>=ArraySize(aKeyword) ){
|
| + jointype |= JT_ERROR;
|
| + break;
|
| + }
|
| + }
|
| + if(
|
| + (jointype & (JT_INNER|JT_OUTER))==(JT_INNER|JT_OUTER) ||
|
| + (jointype & JT_ERROR)!=0
|
| + ){
|
| + const char *zSp = " ";
|
| + assert( pB!=0 );
|
| + if( pC==0 ){ zSp++; }
|
| + sqlite3ErrorMsg(pParse, "unknown or unsupported join type: "
|
| + "%T %T%s%T", pA, pB, zSp, pC);
|
| + jointype = JT_INNER;
|
| + }else if( (jointype & JT_OUTER)!=0
|
| + && (jointype & (JT_LEFT|JT_RIGHT))!=JT_LEFT ){
|
| + sqlite3ErrorMsg(pParse,
|
| + "RIGHT and FULL OUTER JOINs are not currently supported");
|
| + jointype = JT_INNER;
|
| + }
|
| + return jointype;
|
| +}
|
| +
|
| +/*
|
| +** Return the index of a column in a table. Return -1 if the column
|
| +** is not contained in the table.
|
| +*/
|
| +static int columnIndex(Table *pTab, const char *zCol){
|
| + int i;
|
| + for(i=0; i<pTab->nCol; i++){
|
| + if( sqlite3StrICmp(pTab->aCol[i].zName, zCol)==0 ) return i;
|
| + }
|
| + return -1;
|
| +}
|
| +
|
| +/*
|
| +** Search the first N tables in pSrc, from left to right, looking for a
|
| +** table that has a column named zCol.
|
| +**
|
| +** When found, set *piTab and *piCol to the table index and column index
|
| +** of the matching column and return TRUE.
|
| +**
|
| +** If not found, return FALSE.
|
| +*/
|
| +static int tableAndColumnIndex(
|
| + SrcList *pSrc, /* Array of tables to search */
|
| + int N, /* Number of tables in pSrc->a[] to search */
|
| + const char *zCol, /* Name of the column we are looking for */
|
| + int *piTab, /* Write index of pSrc->a[] here */
|
| + int *piCol /* Write index of pSrc->a[*piTab].pTab->aCol[] here */
|
| +){
|
| + int i; /* For looping over tables in pSrc */
|
| + int iCol; /* Index of column matching zCol */
|
| +
|
| + assert( (piTab==0)==(piCol==0) ); /* Both or neither are NULL */
|
| + for(i=0; i<N; i++){
|
| + iCol = columnIndex(pSrc->a[i].pTab, zCol);
|
| + if( iCol>=0 ){
|
| + if( piTab ){
|
| + *piTab = i;
|
| + *piCol = iCol;
|
| + }
|
| + return 1;
|
| + }
|
| + }
|
| + return 0;
|
| +}
|
| +
|
| +/*
|
| +** This function is used to add terms implied by JOIN syntax to the
|
| +** WHERE clause expression of a SELECT statement. The new term, which
|
| +** is ANDed with the existing WHERE clause, is of the form:
|
| +**
|
| +** (tab1.col1 = tab2.col2)
|
| +**
|
| +** where tab1 is the iSrc'th table in SrcList pSrc and tab2 is the
|
| +** (iSrc+1)'th. Column col1 is column iColLeft of tab1, and col2 is
|
| +** column iColRight of tab2.
|
| +*/
|
| +static void addWhereTerm(
|
| + Parse *pParse, /* Parsing context */
|
| + SrcList *pSrc, /* List of tables in FROM clause */
|
| + int iLeft, /* Index of first table to join in pSrc */
|
| + int iColLeft, /* Index of column in first table */
|
| + int iRight, /* Index of second table in pSrc */
|
| + int iColRight, /* Index of column in second table */
|
| + int isOuterJoin, /* True if this is an OUTER join */
|
| + Expr **ppWhere /* IN/OUT: The WHERE clause to add to */
|
| +){
|
| + sqlite3 *db = pParse->db;
|
| + Expr *pE1;
|
| + Expr *pE2;
|
| + Expr *pEq;
|
| +
|
| + assert( iLeft<iRight );
|
| + assert( pSrc->nSrc>iRight );
|
| + assert( pSrc->a[iLeft].pTab );
|
| + assert( pSrc->a[iRight].pTab );
|
| +
|
| + pE1 = sqlite3CreateColumnExpr(db, pSrc, iLeft, iColLeft);
|
| + pE2 = sqlite3CreateColumnExpr(db, pSrc, iRight, iColRight);
|
| +
|
| + pEq = sqlite3PExpr(pParse, TK_EQ, pE1, pE2, 0);
|
| + if( pEq && isOuterJoin ){
|
| + ExprSetProperty(pEq, EP_FromJoin);
|
| + assert( !ExprHasAnyProperty(pEq, EP_TokenOnly|EP_Reduced) );
|
| + ExprSetIrreducible(pEq);
|
| + pEq->iRightJoinTable = (i16)pE2->iTable;
|
| + }
|
| + *ppWhere = sqlite3ExprAnd(db, *ppWhere, pEq);
|
| +}
|
| +
|
| +/*
|
| +** Set the EP_FromJoin property on all terms of the given expression.
|
| +** And set the Expr.iRightJoinTable to iTable for every term in the
|
| +** expression.
|
| +**
|
| +** The EP_FromJoin property is used on terms of an expression to tell
|
| +** the LEFT OUTER JOIN processing logic that this term is part of the
|
| +** join restriction specified in the ON or USING clause and not a part
|
| +** of the more general WHERE clause. These terms are moved over to the
|
| +** WHERE clause during join processing but we need to remember that they
|
| +** originated in the ON or USING clause.
|
| +**
|
| +** The Expr.iRightJoinTable tells the WHERE clause processing that the
|
| +** expression depends on table iRightJoinTable even if that table is not
|
| +** explicitly mentioned in the expression. That information is needed
|
| +** for cases like this:
|
| +**
|
| +** SELECT * FROM t1 LEFT JOIN t2 ON t1.a=t2.b AND t1.x=5
|
| +**
|
| +** The where clause needs to defer the handling of the t1.x=5
|
| +** term until after the t2 loop of the join. In that way, a
|
| +** NULL t2 row will be inserted whenever t1.x!=5. If we do not
|
| +** defer the handling of t1.x=5, it will be processed immediately
|
| +** after the t1 loop and rows with t1.x!=5 will never appear in
|
| +** the output, which is incorrect.
|
| +*/
|
| +static void setJoinExpr(Expr *p, int iTable){
|
| + while( p ){
|
| + ExprSetProperty(p, EP_FromJoin);
|
| + assert( !ExprHasAnyProperty(p, EP_TokenOnly|EP_Reduced) );
|
| + ExprSetIrreducible(p);
|
| + p->iRightJoinTable = (i16)iTable;
|
| + setJoinExpr(p->pLeft, iTable);
|
| + p = p->pRight;
|
| + }
|
| +}
|
| +
|
| +/*
|
| +** This routine processes the join information for a SELECT statement.
|
| +** ON and USING clauses are converted into extra terms of the WHERE clause.
|
| +** NATURAL joins also create extra WHERE clause terms.
|
| +**
|
| +** The terms of a FROM clause are contained in the Select.pSrc structure.
|
| +** The left most table is the first entry in Select.pSrc. The right-most
|
| +** table is the last entry. The join operator is held in the entry to
|
| +** the left. Thus entry 0 contains the join operator for the join between
|
| +** entries 0 and 1. Any ON or USING clauses associated with the join are
|
| +** also attached to the left entry.
|
| +**
|
| +** This routine returns the number of errors encountered.
|
| +*/
|
| +static int sqliteProcessJoin(Parse *pParse, Select *p){
|
| + SrcList *pSrc; /* All tables in the FROM clause */
|
| + int i, j; /* Loop counters */
|
| + struct SrcList_item *pLeft; /* Left table being joined */
|
| + struct SrcList_item *pRight; /* Right table being joined */
|
| +
|
| + pSrc = p->pSrc;
|
| + pLeft = &pSrc->a[0];
|
| + pRight = &pLeft[1];
|
| + for(i=0; i<pSrc->nSrc-1; i++, pRight++, pLeft++){
|
| + Table *pLeftTab = pLeft->pTab;
|
| + Table *pRightTab = pRight->pTab;
|
| + int isOuter;
|
| +
|
| + if( NEVER(pLeftTab==0 || pRightTab==0) ) continue;
|
| + isOuter = (pRight->jointype & JT_OUTER)!=0;
|
| +
|
| + /* When the NATURAL keyword is present, add WHERE clause terms for
|
| + ** every column that the two tables have in common.
|
| + */
|
| + if( pRight->jointype & JT_NATURAL ){
|
| + if( pRight->pOn || pRight->pUsing ){
|
| + sqlite3ErrorMsg(pParse, "a NATURAL join may not have "
|
| + "an ON or USING clause", 0);
|
| + return 1;
|
| + }
|
| + for(j=0; j<pRightTab->nCol; j++){
|
| + char *zName; /* Name of column in the right table */
|
| + int iLeft; /* Matching left table */
|
| + int iLeftCol; /* Matching column in the left table */
|
| +
|
| + zName = pRightTab->aCol[j].zName;
|
| + if( tableAndColumnIndex(pSrc, i+1, zName, &iLeft, &iLeftCol) ){
|
| + addWhereTerm(pParse, pSrc, iLeft, iLeftCol, i+1, j,
|
| + isOuter, &p->pWhere);
|
| + }
|
| + }
|
| + }
|
| +
|
| + /* Disallow both ON and USING clauses in the same join
|
| + */
|
| + if( pRight->pOn && pRight->pUsing ){
|
| + sqlite3ErrorMsg(pParse, "cannot have both ON and USING "
|
| + "clauses in the same join");
|
| + return 1;
|
| + }
|
| +
|
| + /* Add the ON clause to the end of the WHERE clause, connected by
|
| + ** an AND operator.
|
| + */
|
| + if( pRight->pOn ){
|
| + if( isOuter ) setJoinExpr(pRight->pOn, pRight->iCursor);
|
| + p->pWhere = sqlite3ExprAnd(pParse->db, p->pWhere, pRight->pOn);
|
| + pRight->pOn = 0;
|
| + }
|
| +
|
| + /* Create extra terms on the WHERE clause for each column named
|
| + ** in the USING clause. Example: If the two tables to be joined are
|
| + ** A and B and the USING clause names X, Y, and Z, then add this
|
| + ** to the WHERE clause: A.X=B.X AND A.Y=B.Y AND A.Z=B.Z
|
| + ** Report an error if any column mentioned in the USING clause is
|
| + ** not contained in both tables to be joined.
|
| + */
|
| + if( pRight->pUsing ){
|
| + IdList *pList = pRight->pUsing;
|
| + for(j=0; j<pList->nId; j++){
|
| + char *zName; /* Name of the term in the USING clause */
|
| + int iLeft; /* Table on the left with matching column name */
|
| + int iLeftCol; /* Column number of matching column on the left */
|
| + int iRightCol; /* Column number of matching column on the right */
|
| +
|
| + zName = pList->a[j].zName;
|
| + iRightCol = columnIndex(pRightTab, zName);
|
| + if( iRightCol<0
|
| + || !tableAndColumnIndex(pSrc, i+1, zName, &iLeft, &iLeftCol)
|
| + ){
|
| + sqlite3ErrorMsg(pParse, "cannot join using column %s - column "
|
| + "not present in both tables", zName);
|
| + return 1;
|
| + }
|
| + addWhereTerm(pParse, pSrc, iLeft, iLeftCol, i+1, iRightCol,
|
| + isOuter, &p->pWhere);
|
| + }
|
| + }
|
| + }
|
| + return 0;
|
| +}
|
| +
|
| +/*
|
| +** Insert code into "v" that will push the record on the top of the
|
| +** stack into the sorter.
|
| +*/
|
| +static void pushOntoSorter(
|
| + Parse *pParse, /* Parser context */
|
| + ExprList *pOrderBy, /* The ORDER BY clause */
|
| + Select *pSelect, /* The whole SELECT statement */
|
| + int regData /* Register holding data to be sorted */
|
| +){
|
| + Vdbe *v = pParse->pVdbe;
|
| + int nExpr = pOrderBy->nExpr;
|
| + int regBase = sqlite3GetTempRange(pParse, nExpr+2);
|
| + int regRecord = sqlite3GetTempReg(pParse);
|
| + sqlite3ExprCacheClear(pParse);
|
| + sqlite3ExprCodeExprList(pParse, pOrderBy, regBase, 0);
|
| + sqlite3VdbeAddOp2(v, OP_Sequence, pOrderBy->iECursor, regBase+nExpr);
|
| + sqlite3ExprCodeMove(pParse, regData, regBase+nExpr+1, 1);
|
| + sqlite3VdbeAddOp3(v, OP_MakeRecord, regBase, nExpr + 2, regRecord);
|
| + sqlite3VdbeAddOp2(v, OP_IdxInsert, pOrderBy->iECursor, regRecord);
|
| + sqlite3ReleaseTempReg(pParse, regRecord);
|
| + sqlite3ReleaseTempRange(pParse, regBase, nExpr+2);
|
| + if( pSelect->iLimit ){
|
| + int addr1, addr2;
|
| + int iLimit;
|
| + if( pSelect->iOffset ){
|
| + iLimit = pSelect->iOffset+1;
|
| + }else{
|
| + iLimit = pSelect->iLimit;
|
| + }
|
| + addr1 = sqlite3VdbeAddOp1(v, OP_IfZero, iLimit);
|
| + sqlite3VdbeAddOp2(v, OP_AddImm, iLimit, -1);
|
| + addr2 = sqlite3VdbeAddOp0(v, OP_Goto);
|
| + sqlite3VdbeJumpHere(v, addr1);
|
| + sqlite3VdbeAddOp1(v, OP_Last, pOrderBy->iECursor);
|
| + sqlite3VdbeAddOp1(v, OP_Delete, pOrderBy->iECursor);
|
| + sqlite3VdbeJumpHere(v, addr2);
|
| + }
|
| +}
|
| +
|
| +/*
|
| +** Add code to implement the OFFSET
|
| +*/
|
| +static void codeOffset(
|
| + Vdbe *v, /* Generate code into this VM */
|
| + Select *p, /* The SELECT statement being coded */
|
| + int iContinue /* Jump here to skip the current record */
|
| +){
|
| + if( p->iOffset && iContinue!=0 ){
|
| + int addr;
|
| + sqlite3VdbeAddOp2(v, OP_AddImm, p->iOffset, -1);
|
| + addr = sqlite3VdbeAddOp1(v, OP_IfNeg, p->iOffset);
|
| + sqlite3VdbeAddOp2(v, OP_Goto, 0, iContinue);
|
| + VdbeComment((v, "skip OFFSET records"));
|
| + sqlite3VdbeJumpHere(v, addr);
|
| + }
|
| +}
|
| +
|
| +/*
|
| +** Add code that will check to make sure the N registers starting at iMem
|
| +** form a distinct entry. iTab is a sorting index that holds previously
|
| +** seen combinations of the N values. A new entry is made in iTab
|
| +** if the current N values are new.
|
| +**
|
| +** A jump to addrRepeat is made and the N+1 values are popped from the
|
| +** stack if the top N elements are not distinct.
|
| +*/
|
| +static void codeDistinct(
|
| + Parse *pParse, /* Parsing and code generating context */
|
| + int iTab, /* A sorting index used to test for distinctness */
|
| + int addrRepeat, /* Jump to here if not distinct */
|
| + int N, /* Number of elements */
|
| + int iMem /* First element */
|
| +){
|
| + Vdbe *v;
|
| + int r1;
|
| +
|
| + v = pParse->pVdbe;
|
| + r1 = sqlite3GetTempReg(pParse);
|
| + sqlite3VdbeAddOp4Int(v, OP_Found, iTab, addrRepeat, iMem, N);
|
| + sqlite3VdbeAddOp3(v, OP_MakeRecord, iMem, N, r1);
|
| + sqlite3VdbeAddOp2(v, OP_IdxInsert, iTab, r1);
|
| + sqlite3ReleaseTempReg(pParse, r1);
|
| +}
|
| +
|
| +#ifndef SQLITE_OMIT_SUBQUERY
|
| +/*
|
| +** Generate an error message when a SELECT is used within a subexpression
|
| +** (example: "a IN (SELECT * FROM table)") but it has more than 1 result
|
| +** column. We do this in a subroutine because the error used to occur
|
| +** in multiple places. (The error only occurs in one place now, but we
|
| +** retain the subroutine to minimize code disruption.)
|
| +*/
|
| +static int checkForMultiColumnSelectError(
|
| + Parse *pParse, /* Parse context. */
|
| + SelectDest *pDest, /* Destination of SELECT results */
|
| + int nExpr /* Number of result columns returned by SELECT */
|
| +){
|
| + int eDest = pDest->eDest;
|
| + if( nExpr>1 && (eDest==SRT_Mem || eDest==SRT_Set) ){
|
| + sqlite3ErrorMsg(pParse, "only a single result allowed for "
|
| + "a SELECT that is part of an expression");
|
| + return 1;
|
| + }else{
|
| + return 0;
|
| + }
|
| +}
|
| +#endif
|
| +
|
| +/*
|
| +** This routine generates the code for the inside of the inner loop
|
| +** of a SELECT.
|
| +**
|
| +** If srcTab and nColumn are both zero, then the pEList expressions
|
| +** are evaluated in order to get the data for this row. If nColumn>0
|
| +** then data is pulled from srcTab and pEList is used only to get the
|
| +** datatypes for each column.
|
| +*/
|
| +static void selectInnerLoop(
|
| + Parse *pParse, /* The parser context */
|
| + Select *p, /* The complete select statement being coded */
|
| + ExprList *pEList, /* List of values being extracted */
|
| + int srcTab, /* Pull data from this table */
|
| + int nColumn, /* Number of columns in the source table */
|
| + ExprList *pOrderBy, /* If not NULL, sort results using this key */
|
| + int distinct, /* If >=0, make sure results are distinct */
|
| + SelectDest *pDest, /* How to dispose of the results */
|
| + int iContinue, /* Jump here to continue with next row */
|
| + int iBreak /* Jump here to break out of the inner loop */
|
| +){
|
| + Vdbe *v = pParse->pVdbe;
|
| + int i;
|
| + int hasDistinct; /* True if the DISTINCT keyword is present */
|
| + int regResult; /* Start of memory holding result set */
|
| + int eDest = pDest->eDest; /* How to dispose of results */
|
| + int iParm = pDest->iParm; /* First argument to disposal method */
|
| + int nResultCol; /* Number of result columns */
|
| +
|
| + assert( v );
|
| + if( NEVER(v==0) ) return;
|
| + assert( pEList!=0 );
|
| + hasDistinct = distinct>=0;
|
| + if( pOrderBy==0 && !hasDistinct ){
|
| + codeOffset(v, p, iContinue);
|
| + }
|
| +
|
| + /* Pull the requested columns.
|
| + */
|
| + if( nColumn>0 ){
|
| + nResultCol = nColumn;
|
| + }else{
|
| + nResultCol = pEList->nExpr;
|
| + }
|
| + if( pDest->iMem==0 ){
|
| + pDest->iMem = pParse->nMem+1;
|
| + pDest->nMem = nResultCol;
|
| + pParse->nMem += nResultCol;
|
| + }else{
|
| + assert( pDest->nMem==nResultCol );
|
| + }
|
| + regResult = pDest->iMem;
|
| + if( nColumn>0 ){
|
| + for(i=0; i<nColumn; i++){
|
| + sqlite3VdbeAddOp3(v, OP_Column, srcTab, i, regResult+i);
|
| + }
|
| + }else if( eDest!=SRT_Exists ){
|
| + /* If the destination is an EXISTS(...) expression, the actual
|
| + ** values returned by the SELECT are not required.
|
| + */
|
| + sqlite3ExprCacheClear(pParse);
|
| + sqlite3ExprCodeExprList(pParse, pEList, regResult, eDest==SRT_Output);
|
| + }
|
| + nColumn = nResultCol;
|
| +
|
| + /* If the DISTINCT keyword was present on the SELECT statement
|
| + ** and this row has been seen before, then do not make this row
|
| + ** part of the result.
|
| + */
|
| + if( hasDistinct ){
|
| + assert( pEList!=0 );
|
| + assert( pEList->nExpr==nColumn );
|
| + codeDistinct(pParse, distinct, iContinue, nColumn, regResult);
|
| + if( pOrderBy==0 ){
|
| + codeOffset(v, p, iContinue);
|
| + }
|
| + }
|
| +
|
| + switch( eDest ){
|
| + /* In this mode, write each query result to the key of the temporary
|
| + ** table iParm.
|
| + */
|
| +#ifndef SQLITE_OMIT_COMPOUND_SELECT
|
| + case SRT_Union: {
|
| + int r1;
|
| + r1 = sqlite3GetTempReg(pParse);
|
| + sqlite3VdbeAddOp3(v, OP_MakeRecord, regResult, nColumn, r1);
|
| + sqlite3VdbeAddOp2(v, OP_IdxInsert, iParm, r1);
|
| + sqlite3ReleaseTempReg(pParse, r1);
|
| + break;
|
| + }
|
| +
|
| + /* Construct a record from the query result, but instead of
|
| + ** saving that record, use it as a key to delete elements from
|
| + ** the temporary table iParm.
|
| + */
|
| + case SRT_Except: {
|
| + sqlite3VdbeAddOp3(v, OP_IdxDelete, iParm, regResult, nColumn);
|
| + break;
|
| + }
|
| +#endif
|
| +
|
| + /* Store the result as data using a unique key.
|
| + */
|
| + case SRT_Table:
|
| + case SRT_EphemTab: {
|
| + int r1 = sqlite3GetTempReg(pParse);
|
| + testcase( eDest==SRT_Table );
|
| + testcase( eDest==SRT_EphemTab );
|
| + sqlite3VdbeAddOp3(v, OP_MakeRecord, regResult, nColumn, r1);
|
| + if( pOrderBy ){
|
| + pushOntoSorter(pParse, pOrderBy, p, r1);
|
| + }else{
|
| + int r2 = sqlite3GetTempReg(pParse);
|
| + sqlite3VdbeAddOp2(v, OP_NewRowid, iParm, r2);
|
| + sqlite3VdbeAddOp3(v, OP_Insert, iParm, r1, r2);
|
| + sqlite3VdbeChangeP5(v, OPFLAG_APPEND);
|
| + sqlite3ReleaseTempReg(pParse, r2);
|
| + }
|
| + sqlite3ReleaseTempReg(pParse, r1);
|
| + break;
|
| + }
|
| +
|
| +#ifndef SQLITE_OMIT_SUBQUERY
|
| + /* If we are creating a set for an "expr IN (SELECT ...)" construct,
|
| + ** then there should be a single item on the stack. Write this
|
| + ** item into the set table with bogus data.
|
| + */
|
| + case SRT_Set: {
|
| + assert( nColumn==1 );
|
| + p->affinity = sqlite3CompareAffinity(pEList->a[0].pExpr, pDest->affinity);
|
| + if( pOrderBy ){
|
| + /* At first glance you would think we could optimize out the
|
| + ** ORDER BY in this case since the order of entries in the set
|
| + ** does not matter. But there might be a LIMIT clause, in which
|
| + ** case the order does matter */
|
| + pushOntoSorter(pParse, pOrderBy, p, regResult);
|
| + }else{
|
| + int r1 = sqlite3GetTempReg(pParse);
|
| + sqlite3VdbeAddOp4(v, OP_MakeRecord, regResult, 1, r1, &p->affinity, 1);
|
| + sqlite3ExprCacheAffinityChange(pParse, regResult, 1);
|
| + sqlite3VdbeAddOp2(v, OP_IdxInsert, iParm, r1);
|
| + sqlite3ReleaseTempReg(pParse, r1);
|
| + }
|
| + break;
|
| + }
|
| +
|
| + /* If any row exist in the result set, record that fact and abort.
|
| + */
|
| + case SRT_Exists: {
|
| + sqlite3VdbeAddOp2(v, OP_Integer, 1, iParm);
|
| + /* The LIMIT clause will terminate the loop for us */
|
| + break;
|
| + }
|
| +
|
| + /* If this is a scalar select that is part of an expression, then
|
| + ** store the results in the appropriate memory cell and break out
|
| + ** of the scan loop.
|
| + */
|
| + case SRT_Mem: {
|
| + assert( nColumn==1 );
|
| + if( pOrderBy ){
|
| + pushOntoSorter(pParse, pOrderBy, p, regResult);
|
| + }else{
|
| + sqlite3ExprCodeMove(pParse, regResult, iParm, 1);
|
| + /* The LIMIT clause will jump out of the loop for us */
|
| + }
|
| + break;
|
| + }
|
| +#endif /* #ifndef SQLITE_OMIT_SUBQUERY */
|
| +
|
| + /* Send the data to the callback function or to a subroutine. In the
|
| + ** case of a subroutine, the subroutine itself is responsible for
|
| + ** popping the data from the stack.
|
| + */
|
| + case SRT_Coroutine:
|
| + case SRT_Output: {
|
| + testcase( eDest==SRT_Coroutine );
|
| + testcase( eDest==SRT_Output );
|
| + if( pOrderBy ){
|
| + int r1 = sqlite3GetTempReg(pParse);
|
| + sqlite3VdbeAddOp3(v, OP_MakeRecord, regResult, nColumn, r1);
|
| + pushOntoSorter(pParse, pOrderBy, p, r1);
|
| + sqlite3ReleaseTempReg(pParse, r1);
|
| + }else if( eDest==SRT_Coroutine ){
|
| + sqlite3VdbeAddOp1(v, OP_Yield, pDest->iParm);
|
| + }else{
|
| + sqlite3VdbeAddOp2(v, OP_ResultRow, regResult, nColumn);
|
| + sqlite3ExprCacheAffinityChange(pParse, regResult, nColumn);
|
| + }
|
| + break;
|
| + }
|
| +
|
| +#if !defined(SQLITE_OMIT_TRIGGER)
|
| + /* Discard the results. This is used for SELECT statements inside
|
| + ** the body of a TRIGGER. The purpose of such selects is to call
|
| + ** user-defined functions that have side effects. We do not care
|
| + ** about the actual results of the select.
|
| + */
|
| + default: {
|
| + assert( eDest==SRT_Discard );
|
| + break;
|
| + }
|
| +#endif
|
| + }
|
| +
|
| + /* Jump to the end of the loop if the LIMIT is reached. Except, if
|
| + ** there is a sorter, in which case the sorter has already limited
|
| + ** the output for us.
|
| + */
|
| + if( pOrderBy==0 && p->iLimit ){
|
| + sqlite3VdbeAddOp3(v, OP_IfZero, p->iLimit, iBreak, -1);
|
| + }
|
| +}
|
| +
|
| +/*
|
| +** Given an expression list, generate a KeyInfo structure that records
|
| +** the collating sequence for each expression in that expression list.
|
| +**
|
| +** If the ExprList is an ORDER BY or GROUP BY clause then the resulting
|
| +** KeyInfo structure is appropriate for initializing a virtual index to
|
| +** implement that clause. If the ExprList is the result set of a SELECT
|
| +** then the KeyInfo structure is appropriate for initializing a virtual
|
| +** index to implement a DISTINCT test.
|
| +**
|
| +** Space to hold the KeyInfo structure is obtain from malloc. The calling
|
| +** function is responsible for seeing that this structure is eventually
|
| +** freed. Add the KeyInfo structure to the P4 field of an opcode using
|
| +** P4_KEYINFO_HANDOFF is the usual way of dealing with this.
|
| +*/
|
| +static KeyInfo *keyInfoFromExprList(Parse *pParse, ExprList *pList){
|
| + sqlite3 *db = pParse->db;
|
| + int nExpr;
|
| + KeyInfo *pInfo;
|
| + struct ExprList_item *pItem;
|
| + int i;
|
| +
|
| + nExpr = pList->nExpr;
|
| + pInfo = sqlite3DbMallocZero(db, sizeof(*pInfo) + nExpr*(sizeof(CollSeq*)+1) );
|
| + if( pInfo ){
|
| + pInfo->aSortOrder = (u8*)&pInfo->aColl[nExpr];
|
| + pInfo->nField = (u16)nExpr;
|
| + pInfo->enc = ENC(db);
|
| + pInfo->db = db;
|
| + for(i=0, pItem=pList->a; i<nExpr; i++, pItem++){
|
| + CollSeq *pColl;
|
| + pColl = sqlite3ExprCollSeq(pParse, pItem->pExpr);
|
| + if( !pColl ){
|
| + pColl = db->pDfltColl;
|
| + }
|
| + pInfo->aColl[i] = pColl;
|
| + pInfo->aSortOrder[i] = pItem->sortOrder;
|
| + }
|
| + }
|
| + return pInfo;
|
| +}
|
| +
|
| +#ifndef SQLITE_OMIT_COMPOUND_SELECT
|
| +/*
|
| +** Name of the connection operator, used for error messages.
|
| +*/
|
| +static const char *selectOpName(int id){
|
| + char *z;
|
| + switch( id ){
|
| + case TK_ALL: z = "UNION ALL"; break;
|
| + case TK_INTERSECT: z = "INTERSECT"; break;
|
| + case TK_EXCEPT: z = "EXCEPT"; break;
|
| + default: z = "UNION"; break;
|
| + }
|
| + return z;
|
| +}
|
| +#endif /* SQLITE_OMIT_COMPOUND_SELECT */
|
| +
|
| +#ifndef SQLITE_OMIT_EXPLAIN
|
| +/*
|
| +** Unless an "EXPLAIN QUERY PLAN" command is being processed, this function
|
| +** is a no-op. Otherwise, it adds a single row of output to the EQP result,
|
| +** where the caption is of the form:
|
| +**
|
| +** "USE TEMP B-TREE FOR xxx"
|
| +**
|
| +** where xxx is one of "DISTINCT", "ORDER BY" or "GROUP BY". Exactly which
|
| +** is determined by the zUsage argument.
|
| +*/
|
| +static void explainTempTable(Parse *pParse, const char *zUsage){
|
| + if( pParse->explain==2 ){
|
| + Vdbe *v = pParse->pVdbe;
|
| + char *zMsg = sqlite3MPrintf(pParse->db, "USE TEMP B-TREE FOR %s", zUsage);
|
| + sqlite3VdbeAddOp4(v, OP_Explain, pParse->iSelectId, 0, 0, zMsg, P4_DYNAMIC);
|
| + }
|
| +}
|
| +
|
| +/*
|
| +** Assign expression b to lvalue a. A second, no-op, version of this macro
|
| +** is provided when SQLITE_OMIT_EXPLAIN is defined. This allows the code
|
| +** in sqlite3Select() to assign values to structure member variables that
|
| +** only exist if SQLITE_OMIT_EXPLAIN is not defined without polluting the
|
| +** code with #ifndef directives.
|
| +*/
|
| +# define explainSetInteger(a, b) a = b
|
| +
|
| +#else
|
| +/* No-op versions of the explainXXX() functions and macros. */
|
| +# define explainTempTable(y,z)
|
| +# define explainSetInteger(y,z)
|
| +#endif
|
| +
|
| +#if !defined(SQLITE_OMIT_EXPLAIN) && !defined(SQLITE_OMIT_COMPOUND_SELECT)
|
| +/*
|
| +** Unless an "EXPLAIN QUERY PLAN" command is being processed, this function
|
| +** is a no-op. Otherwise, it adds a single row of output to the EQP result,
|
| +** where the caption is of one of the two forms:
|
| +**
|
| +** "COMPOSITE SUBQUERIES iSub1 and iSub2 (op)"
|
| +** "COMPOSITE SUBQUERIES iSub1 and iSub2 USING TEMP B-TREE (op)"
|
| +**
|
| +** where iSub1 and iSub2 are the integers passed as the corresponding
|
| +** function parameters, and op is the text representation of the parameter
|
| +** of the same name. The parameter "op" must be one of TK_UNION, TK_EXCEPT,
|
| +** TK_INTERSECT or TK_ALL. The first form is used if argument bUseTmp is
|
| +** false, or the second form if it is true.
|
| +*/
|
| +static void explainComposite(
|
| + Parse *pParse, /* Parse context */
|
| + int op, /* One of TK_UNION, TK_EXCEPT etc. */
|
| + int iSub1, /* Subquery id 1 */
|
| + int iSub2, /* Subquery id 2 */
|
| + int bUseTmp /* True if a temp table was used */
|
| +){
|
| + assert( op==TK_UNION || op==TK_EXCEPT || op==TK_INTERSECT || op==TK_ALL );
|
| + if( pParse->explain==2 ){
|
| + Vdbe *v = pParse->pVdbe;
|
| + char *zMsg = sqlite3MPrintf(
|
| + pParse->db, "COMPOUND SUBQUERIES %d AND %d %s(%s)", iSub1, iSub2,
|
| + bUseTmp?"USING TEMP B-TREE ":"", selectOpName(op)
|
| + );
|
| + sqlite3VdbeAddOp4(v, OP_Explain, pParse->iSelectId, 0, 0, zMsg, P4_DYNAMIC);
|
| + }
|
| +}
|
| +#else
|
| +/* No-op versions of the explainXXX() functions and macros. */
|
| +# define explainComposite(v,w,x,y,z)
|
| +#endif
|
| +
|
| +/*
|
| +** If the inner loop was generated using a non-null pOrderBy argument,
|
| +** then the results were placed in a sorter. After the loop is terminated
|
| +** we need to run the sorter and output the results. The following
|
| +** routine generates the code needed to do that.
|
| +*/
|
| +static void generateSortTail(
|
| + Parse *pParse, /* Parsing context */
|
| + Select *p, /* The SELECT statement */
|
| + Vdbe *v, /* Generate code into this VDBE */
|
| + int nColumn, /* Number of columns of data */
|
| + SelectDest *pDest /* Write the sorted results here */
|
| +){
|
| + int addrBreak = sqlite3VdbeMakeLabel(v); /* Jump here to exit loop */
|
| + int addrContinue = sqlite3VdbeMakeLabel(v); /* Jump here for next cycle */
|
| + int addr;
|
| + int iTab;
|
| + int pseudoTab = 0;
|
| + ExprList *pOrderBy = p->pOrderBy;
|
| +
|
| + int eDest = pDest->eDest;
|
| + int iParm = pDest->iParm;
|
| +
|
| + int regRow;
|
| + int regRowid;
|
| +
|
| + iTab = pOrderBy->iECursor;
|
| + regRow = sqlite3GetTempReg(pParse);
|
| + if( eDest==SRT_Output || eDest==SRT_Coroutine ){
|
| + pseudoTab = pParse->nTab++;
|
| + sqlite3VdbeAddOp3(v, OP_OpenPseudo, pseudoTab, regRow, nColumn);
|
| + regRowid = 0;
|
| + }else{
|
| + regRowid = sqlite3GetTempReg(pParse);
|
| + }
|
| + addr = 1 + sqlite3VdbeAddOp2(v, OP_Sort, iTab, addrBreak);
|
| + codeOffset(v, p, addrContinue);
|
| + sqlite3VdbeAddOp3(v, OP_Column, iTab, pOrderBy->nExpr + 1, regRow);
|
| + switch( eDest ){
|
| + case SRT_Table:
|
| + case SRT_EphemTab: {
|
| + testcase( eDest==SRT_Table );
|
| + testcase( eDest==SRT_EphemTab );
|
| + sqlite3VdbeAddOp2(v, OP_NewRowid, iParm, regRowid);
|
| + sqlite3VdbeAddOp3(v, OP_Insert, iParm, regRow, regRowid);
|
| + sqlite3VdbeChangeP5(v, OPFLAG_APPEND);
|
| + break;
|
| + }
|
| +#ifndef SQLITE_OMIT_SUBQUERY
|
| + case SRT_Set: {
|
| + assert( nColumn==1 );
|
| + sqlite3VdbeAddOp4(v, OP_MakeRecord, regRow, 1, regRowid, &p->affinity, 1);
|
| + sqlite3ExprCacheAffinityChange(pParse, regRow, 1);
|
| + sqlite3VdbeAddOp2(v, OP_IdxInsert, iParm, regRowid);
|
| + break;
|
| + }
|
| + case SRT_Mem: {
|
| + assert( nColumn==1 );
|
| + sqlite3ExprCodeMove(pParse, regRow, iParm, 1);
|
| + /* The LIMIT clause will terminate the loop for us */
|
| + break;
|
| + }
|
| +#endif
|
| + default: {
|
| + int i;
|
| + assert( eDest==SRT_Output || eDest==SRT_Coroutine );
|
| + testcase( eDest==SRT_Output );
|
| + testcase( eDest==SRT_Coroutine );
|
| + for(i=0; i<nColumn; i++){
|
| + assert( regRow!=pDest->iMem+i );
|
| + sqlite3VdbeAddOp3(v, OP_Column, pseudoTab, i, pDest->iMem+i);
|
| + if( i==0 ){
|
| + sqlite3VdbeChangeP5(v, OPFLAG_CLEARCACHE);
|
| + }
|
| + }
|
| + if( eDest==SRT_Output ){
|
| + sqlite3VdbeAddOp2(v, OP_ResultRow, pDest->iMem, nColumn);
|
| + sqlite3ExprCacheAffinityChange(pParse, pDest->iMem, nColumn);
|
| + }else{
|
| + sqlite3VdbeAddOp1(v, OP_Yield, pDest->iParm);
|
| + }
|
| + break;
|
| + }
|
| + }
|
| + sqlite3ReleaseTempReg(pParse, regRow);
|
| + sqlite3ReleaseTempReg(pParse, regRowid);
|
| +
|
| + /* The bottom of the loop
|
| + */
|
| + sqlite3VdbeResolveLabel(v, addrContinue);
|
| + sqlite3VdbeAddOp2(v, OP_Next, iTab, addr);
|
| + sqlite3VdbeResolveLabel(v, addrBreak);
|
| + if( eDest==SRT_Output || eDest==SRT_Coroutine ){
|
| + sqlite3VdbeAddOp2(v, OP_Close, pseudoTab, 0);
|
| + }
|
| +}
|
| +
|
| +/*
|
| +** Return a pointer to a string containing the 'declaration type' of the
|
| +** expression pExpr. The string may be treated as static by the caller.
|
| +**
|
| +** The declaration type is the exact datatype definition extracted from the
|
| +** original CREATE TABLE statement if the expression is a column. The
|
| +** declaration type for a ROWID field is INTEGER. Exactly when an expression
|
| +** is considered a column can be complex in the presence of subqueries. The
|
| +** result-set expression in all of the following SELECT statements is
|
| +** considered a column by this function.
|
| +**
|
| +** SELECT col FROM tbl;
|
| +** SELECT (SELECT col FROM tbl;
|
| +** SELECT (SELECT col FROM tbl);
|
| +** SELECT abc FROM (SELECT col AS abc FROM tbl);
|
| +**
|
| +** The declaration type for any expression other than a column is NULL.
|
| +*/
|
| +static const char *columnType(
|
| + NameContext *pNC,
|
| + Expr *pExpr,
|
| + const char **pzOriginDb,
|
| + const char **pzOriginTab,
|
| + const char **pzOriginCol
|
| +){
|
| + char const *zType = 0;
|
| + char const *zOriginDb = 0;
|
| + char const *zOriginTab = 0;
|
| + char const *zOriginCol = 0;
|
| + int j;
|
| + if( NEVER(pExpr==0) || pNC->pSrcList==0 ) return 0;
|
| +
|
| + switch( pExpr->op ){
|
| + case TK_AGG_COLUMN:
|
| + case TK_COLUMN: {
|
| + /* The expression is a column. Locate the table the column is being
|
| + ** extracted from in NameContext.pSrcList. This table may be real
|
| + ** database table or a subquery.
|
| + */
|
| + Table *pTab = 0; /* Table structure column is extracted from */
|
| + Select *pS = 0; /* Select the column is extracted from */
|
| + int iCol = pExpr->iColumn; /* Index of column in pTab */
|
| + testcase( pExpr->op==TK_AGG_COLUMN );
|
| + testcase( pExpr->op==TK_COLUMN );
|
| + while( pNC && !pTab ){
|
| + SrcList *pTabList = pNC->pSrcList;
|
| + for(j=0;j<pTabList->nSrc && pTabList->a[j].iCursor!=pExpr->iTable;j++);
|
| + if( j<pTabList->nSrc ){
|
| + pTab = pTabList->a[j].pTab;
|
| + pS = pTabList->a[j].pSelect;
|
| + }else{
|
| + pNC = pNC->pNext;
|
| + }
|
| + }
|
| +
|
| + if( pTab==0 ){
|
| + /* At one time, code such as "SELECT new.x" within a trigger would
|
| + ** cause this condition to run. Since then, we have restructured how
|
| + ** trigger code is generated and so this condition is no longer
|
| + ** possible. However, it can still be true for statements like
|
| + ** the following:
|
| + **
|
| + ** CREATE TABLE t1(col INTEGER);
|
| + ** SELECT (SELECT t1.col) FROM FROM t1;
|
| + **
|
| + ** when columnType() is called on the expression "t1.col" in the
|
| + ** sub-select. In this case, set the column type to NULL, even
|
| + ** though it should really be "INTEGER".
|
| + **
|
| + ** This is not a problem, as the column type of "t1.col" is never
|
| + ** used. When columnType() is called on the expression
|
| + ** "(SELECT t1.col)", the correct type is returned (see the TK_SELECT
|
| + ** branch below. */
|
| + break;
|
| + }
|
| +
|
| + assert( pTab && pExpr->pTab==pTab );
|
| + if( pS ){
|
| + /* The "table" is actually a sub-select or a view in the FROM clause
|
| + ** of the SELECT statement. Return the declaration type and origin
|
| + ** data for the result-set column of the sub-select.
|
| + */
|
| + if( iCol>=0 && ALWAYS(iCol<pS->pEList->nExpr) ){
|
| + /* If iCol is less than zero, then the expression requests the
|
| + ** rowid of the sub-select or view. This expression is legal (see
|
| + ** test case misc2.2.2) - it always evaluates to NULL.
|
| + */
|
| + NameContext sNC;
|
| + Expr *p = pS->pEList->a[iCol].pExpr;
|
| + sNC.pSrcList = pS->pSrc;
|
| + sNC.pNext = pNC;
|
| + sNC.pParse = pNC->pParse;
|
| + zType = columnType(&sNC, p, &zOriginDb, &zOriginTab, &zOriginCol);
|
| + }
|
| + }else if( ALWAYS(pTab->pSchema) ){
|
| + /* A real table */
|
| + assert( !pS );
|
| + if( iCol<0 ) iCol = pTab->iPKey;
|
| + assert( iCol==-1 || (iCol>=0 && iCol<pTab->nCol) );
|
| + if( iCol<0 ){
|
| + zType = "INTEGER";
|
| + zOriginCol = "rowid";
|
| + }else{
|
| + zType = pTab->aCol[iCol].zType;
|
| + zOriginCol = pTab->aCol[iCol].zName;
|
| + }
|
| + zOriginTab = pTab->zName;
|
| + if( pNC->pParse ){
|
| + int iDb = sqlite3SchemaToIndex(pNC->pParse->db, pTab->pSchema);
|
| + zOriginDb = pNC->pParse->db->aDb[iDb].zName;
|
| + }
|
| + }
|
| + break;
|
| + }
|
| +#ifndef SQLITE_OMIT_SUBQUERY
|
| + case TK_SELECT: {
|
| + /* The expression is a sub-select. Return the declaration type and
|
| + ** origin info for the single column in the result set of the SELECT
|
| + ** statement.
|
| + */
|
| + NameContext sNC;
|
| + Select *pS = pExpr->x.pSelect;
|
| + Expr *p = pS->pEList->a[0].pExpr;
|
| + assert( ExprHasProperty(pExpr, EP_xIsSelect) );
|
| + sNC.pSrcList = pS->pSrc;
|
| + sNC.pNext = pNC;
|
| + sNC.pParse = pNC->pParse;
|
| + zType = columnType(&sNC, p, &zOriginDb, &zOriginTab, &zOriginCol);
|
| + break;
|
| + }
|
| +#endif
|
| + }
|
| +
|
| + if( pzOriginDb ){
|
| + assert( pzOriginTab && pzOriginCol );
|
| + *pzOriginDb = zOriginDb;
|
| + *pzOriginTab = zOriginTab;
|
| + *pzOriginCol = zOriginCol;
|
| + }
|
| + return zType;
|
| +}
|
| +
|
| +/*
|
| +** Generate code that will tell the VDBE the declaration types of columns
|
| +** in the result set.
|
| +*/
|
| +static void generateColumnTypes(
|
| + Parse *pParse, /* Parser context */
|
| + SrcList *pTabList, /* List of tables */
|
| + ExprList *pEList /* Expressions defining the result set */
|
| +){
|
| +#ifndef SQLITE_OMIT_DECLTYPE
|
| + Vdbe *v = pParse->pVdbe;
|
| + int i;
|
| + NameContext sNC;
|
| + sNC.pSrcList = pTabList;
|
| + sNC.pParse = pParse;
|
| + for(i=0; i<pEList->nExpr; i++){
|
| + Expr *p = pEList->a[i].pExpr;
|
| + const char *zType;
|
| +#ifdef SQLITE_ENABLE_COLUMN_METADATA
|
| + const char *zOrigDb = 0;
|
| + const char *zOrigTab = 0;
|
| + const char *zOrigCol = 0;
|
| + zType = columnType(&sNC, p, &zOrigDb, &zOrigTab, &zOrigCol);
|
| +
|
| + /* The vdbe must make its own copy of the column-type and other
|
| + ** column specific strings, in case the schema is reset before this
|
| + ** virtual machine is deleted.
|
| + */
|
| + sqlite3VdbeSetColName(v, i, COLNAME_DATABASE, zOrigDb, SQLITE_TRANSIENT);
|
| + sqlite3VdbeSetColName(v, i, COLNAME_TABLE, zOrigTab, SQLITE_TRANSIENT);
|
| + sqlite3VdbeSetColName(v, i, COLNAME_COLUMN, zOrigCol, SQLITE_TRANSIENT);
|
| +#else
|
| + zType = columnType(&sNC, p, 0, 0, 0);
|
| +#endif
|
| + sqlite3VdbeSetColName(v, i, COLNAME_DECLTYPE, zType, SQLITE_TRANSIENT);
|
| + }
|
| +#endif /* SQLITE_OMIT_DECLTYPE */
|
| +}
|
| +
|
| +/*
|
| +** Generate code that will tell the VDBE the names of columns
|
| +** in the result set. This information is used to provide the
|
| +** azCol[] values in the callback.
|
| +*/
|
| +static void generateColumnNames(
|
| + Parse *pParse, /* Parser context */
|
| + SrcList *pTabList, /* List of tables */
|
| + ExprList *pEList /* Expressions defining the result set */
|
| +){
|
| + Vdbe *v = pParse->pVdbe;
|
| + int i, j;
|
| + sqlite3 *db = pParse->db;
|
| + int fullNames, shortNames;
|
| +
|
| +#ifndef SQLITE_OMIT_EXPLAIN
|
| + /* If this is an EXPLAIN, skip this step */
|
| + if( pParse->explain ){
|
| + return;
|
| + }
|
| +#endif
|
| +
|
| + if( pParse->colNamesSet || NEVER(v==0) || db->mallocFailed ) return;
|
| + pParse->colNamesSet = 1;
|
| + fullNames = (db->flags & SQLITE_FullColNames)!=0;
|
| + shortNames = (db->flags & SQLITE_ShortColNames)!=0;
|
| + sqlite3VdbeSetNumCols(v, pEList->nExpr);
|
| + for(i=0; i<pEList->nExpr; i++){
|
| + Expr *p;
|
| + p = pEList->a[i].pExpr;
|
| + if( NEVER(p==0) ) continue;
|
| + if( pEList->a[i].zName ){
|
| + char *zName = pEList->a[i].zName;
|
| + sqlite3VdbeSetColName(v, i, COLNAME_NAME, zName, SQLITE_TRANSIENT);
|
| + }else if( (p->op==TK_COLUMN || p->op==TK_AGG_COLUMN) && pTabList ){
|
| + Table *pTab;
|
| + char *zCol;
|
| + int iCol = p->iColumn;
|
| + for(j=0; ALWAYS(j<pTabList->nSrc); j++){
|
| + if( pTabList->a[j].iCursor==p->iTable ) break;
|
| + }
|
| + assert( j<pTabList->nSrc );
|
| + pTab = pTabList->a[j].pTab;
|
| + if( iCol<0 ) iCol = pTab->iPKey;
|
| + assert( iCol==-1 || (iCol>=0 && iCol<pTab->nCol) );
|
| + if( iCol<0 ){
|
| + zCol = "rowid";
|
| + }else{
|
| + zCol = pTab->aCol[iCol].zName;
|
| + }
|
| + if( !shortNames && !fullNames ){
|
| + sqlite3VdbeSetColName(v, i, COLNAME_NAME,
|
| + sqlite3DbStrDup(db, pEList->a[i].zSpan), SQLITE_DYNAMIC);
|
| + }else if( fullNames ){
|
| + char *zName = 0;
|
| + zName = sqlite3MPrintf(db, "%s.%s", pTab->zName, zCol);
|
| + sqlite3VdbeSetColName(v, i, COLNAME_NAME, zName, SQLITE_DYNAMIC);
|
| + }else{
|
| + sqlite3VdbeSetColName(v, i, COLNAME_NAME, zCol, SQLITE_TRANSIENT);
|
| + }
|
| + }else{
|
| + sqlite3VdbeSetColName(v, i, COLNAME_NAME,
|
| + sqlite3DbStrDup(db, pEList->a[i].zSpan), SQLITE_DYNAMIC);
|
| + }
|
| + }
|
| + generateColumnTypes(pParse, pTabList, pEList);
|
| +}
|
| +
|
| +/*
|
| +** Given a an expression list (which is really the list of expressions
|
| +** that form the result set of a SELECT statement) compute appropriate
|
| +** column names for a table that would hold the expression list.
|
| +**
|
| +** All column names will be unique.
|
| +**
|
| +** Only the column names are computed. Column.zType, Column.zColl,
|
| +** and other fields of Column are zeroed.
|
| +**
|
| +** Return SQLITE_OK on success. If a memory allocation error occurs,
|
| +** store NULL in *paCol and 0 in *pnCol and return SQLITE_NOMEM.
|
| +*/
|
| +static int selectColumnsFromExprList(
|
| + Parse *pParse, /* Parsing context */
|
| + ExprList *pEList, /* Expr list from which to derive column names */
|
| + int *pnCol, /* Write the number of columns here */
|
| + Column **paCol /* Write the new column list here */
|
| +){
|
| + sqlite3 *db = pParse->db; /* Database connection */
|
| + int i, j; /* Loop counters */
|
| + int cnt; /* Index added to make the name unique */
|
| + Column *aCol, *pCol; /* For looping over result columns */
|
| + int nCol; /* Number of columns in the result set */
|
| + Expr *p; /* Expression for a single result column */
|
| + char *zName; /* Column name */
|
| + int nName; /* Size of name in zName[] */
|
| +
|
| + *pnCol = nCol = pEList->nExpr;
|
| + aCol = *paCol = sqlite3DbMallocZero(db, sizeof(aCol[0])*nCol);
|
| + if( aCol==0 ) return SQLITE_NOMEM;
|
| + for(i=0, pCol=aCol; i<nCol; i++, pCol++){
|
| + /* Get an appropriate name for the column
|
| + */
|
| + p = pEList->a[i].pExpr;
|
| + assert( p->pRight==0 || ExprHasProperty(p->pRight, EP_IntValue)
|
| + || p->pRight->u.zToken==0 || p->pRight->u.zToken[0]!=0 );
|
| + if( (zName = pEList->a[i].zName)!=0 ){
|
| + /* If the column contains an "AS <name>" phrase, use <name> as the name */
|
| + zName = sqlite3DbStrDup(db, zName);
|
| + }else{
|
| + Expr *pColExpr = p; /* The expression that is the result column name */
|
| + Table *pTab; /* Table associated with this expression */
|
| + while( pColExpr->op==TK_DOT ) pColExpr = pColExpr->pRight;
|
| + if( pColExpr->op==TK_COLUMN && ALWAYS(pColExpr->pTab!=0) ){
|
| + /* For columns use the column name name */
|
| + int iCol = pColExpr->iColumn;
|
| + pTab = pColExpr->pTab;
|
| + if( iCol<0 ) iCol = pTab->iPKey;
|
| + zName = sqlite3MPrintf(db, "%s",
|
| + iCol>=0 ? pTab->aCol[iCol].zName : "rowid");
|
| + }else if( pColExpr->op==TK_ID ){
|
| + assert( !ExprHasProperty(pColExpr, EP_IntValue) );
|
| + zName = sqlite3MPrintf(db, "%s", pColExpr->u.zToken);
|
| + }else{
|
| + /* Use the original text of the column expression as its name */
|
| + zName = sqlite3MPrintf(db, "%s", pEList->a[i].zSpan);
|
| + }
|
| + }
|
| + if( db->mallocFailed ){
|
| + sqlite3DbFree(db, zName);
|
| + break;
|
| + }
|
| +
|
| + /* Make sure the column name is unique. If the name is not unique,
|
| + ** append a integer to the name so that it becomes unique.
|
| + */
|
| + nName = sqlite3Strlen30(zName);
|
| + for(j=cnt=0; j<i; j++){
|
| + if( sqlite3StrICmp(aCol[j].zName, zName)==0 ){
|
| + char *zNewName;
|
| + zName[nName] = 0;
|
| + zNewName = sqlite3MPrintf(db, "%s:%d", zName, ++cnt);
|
| + sqlite3DbFree(db, zName);
|
| + zName = zNewName;
|
| + j = -1;
|
| + if( zName==0 ) break;
|
| + }
|
| + }
|
| + pCol->zName = zName;
|
| + }
|
| + if( db->mallocFailed ){
|
| + for(j=0; j<i; j++){
|
| + sqlite3DbFree(db, aCol[j].zName);
|
| + }
|
| + sqlite3DbFree(db, aCol);
|
| + *paCol = 0;
|
| + *pnCol = 0;
|
| + return SQLITE_NOMEM;
|
| + }
|
| + return SQLITE_OK;
|
| +}
|
| +
|
| +/*
|
| +** Add type and collation information to a column list based on
|
| +** a SELECT statement.
|
| +**
|
| +** The column list presumably came from selectColumnNamesFromExprList().
|
| +** The column list has only names, not types or collations. This
|
| +** routine goes through and adds the types and collations.
|
| +**
|
| +** This routine requires that all identifiers in the SELECT
|
| +** statement be resolved.
|
| +*/
|
| +static void selectAddColumnTypeAndCollation(
|
| + Parse *pParse, /* Parsing contexts */
|
| + int nCol, /* Number of columns */
|
| + Column *aCol, /* List of columns */
|
| + Select *pSelect /* SELECT used to determine types and collations */
|
| +){
|
| + sqlite3 *db = pParse->db;
|
| + NameContext sNC;
|
| + Column *pCol;
|
| + CollSeq *pColl;
|
| + int i;
|
| + Expr *p;
|
| + struct ExprList_item *a;
|
| +
|
| + assert( pSelect!=0 );
|
| + assert( (pSelect->selFlags & SF_Resolved)!=0 );
|
| + assert( nCol==pSelect->pEList->nExpr || db->mallocFailed );
|
| + if( db->mallocFailed ) return;
|
| + memset(&sNC, 0, sizeof(sNC));
|
| + sNC.pSrcList = pSelect->pSrc;
|
| + a = pSelect->pEList->a;
|
| + for(i=0, pCol=aCol; i<nCol; i++, pCol++){
|
| + p = a[i].pExpr;
|
| + pCol->zType = sqlite3DbStrDup(db, columnType(&sNC, p, 0, 0, 0));
|
| + pCol->affinity = sqlite3ExprAffinity(p);
|
| + if( pCol->affinity==0 ) pCol->affinity = SQLITE_AFF_NONE;
|
| + pColl = sqlite3ExprCollSeq(pParse, p);
|
| + if( pColl ){
|
| + pCol->zColl = sqlite3DbStrDup(db, pColl->zName);
|
| + }
|
| + }
|
| +}
|
| +
|
| +/*
|
| +** Given a SELECT statement, generate a Table structure that describes
|
| +** the result set of that SELECT.
|
| +*/
|
| +Table *sqlite3ResultSetOfSelect(Parse *pParse, Select *pSelect){
|
| + Table *pTab;
|
| + sqlite3 *db = pParse->db;
|
| + int savedFlags;
|
| +
|
| + savedFlags = db->flags;
|
| + db->flags &= ~SQLITE_FullColNames;
|
| + db->flags |= SQLITE_ShortColNames;
|
| + sqlite3SelectPrep(pParse, pSelect, 0);
|
| + if( pParse->nErr ) return 0;
|
| + while( pSelect->pPrior ) pSelect = pSelect->pPrior;
|
| + db->flags = savedFlags;
|
| + pTab = sqlite3DbMallocZero(db, sizeof(Table) );
|
| + if( pTab==0 ){
|
| + return 0;
|
| + }
|
| + /* The sqlite3ResultSetOfSelect() is only used n contexts where lookaside
|
| + ** is disabled */
|
| + assert( db->lookaside.bEnabled==0 );
|
| + pTab->nRef = 1;
|
| + pTab->zName = 0;
|
| + pTab->nRowEst = 1000000;
|
| + selectColumnsFromExprList(pParse, pSelect->pEList, &pTab->nCol, &pTab->aCol);
|
| + selectAddColumnTypeAndCollation(pParse, pTab->nCol, pTab->aCol, pSelect);
|
| + pTab->iPKey = -1;
|
| + if( db->mallocFailed ){
|
| + sqlite3DeleteTable(db, pTab);
|
| + return 0;
|
| + }
|
| + return pTab;
|
| +}
|
| +
|
| +/*
|
| +** Get a VDBE for the given parser context. Create a new one if necessary.
|
| +** If an error occurs, return NULL and leave a message in pParse.
|
| +*/
|
| +Vdbe *sqlite3GetVdbe(Parse *pParse){
|
| + Vdbe *v = pParse->pVdbe;
|
| + if( v==0 ){
|
| + v = pParse->pVdbe = sqlite3VdbeCreate(pParse->db);
|
| +#ifndef SQLITE_OMIT_TRACE
|
| + if( v ){
|
| + sqlite3VdbeAddOp0(v, OP_Trace);
|
| + }
|
| +#endif
|
| + }
|
| + return v;
|
| +}
|
| +
|
| +
|
| +/*
|
| +** Compute the iLimit and iOffset fields of the SELECT based on the
|
| +** pLimit and pOffset expressions. pLimit and pOffset hold the expressions
|
| +** that appear in the original SQL statement after the LIMIT and OFFSET
|
| +** keywords. Or NULL if those keywords are omitted. iLimit and iOffset
|
| +** are the integer memory register numbers for counters used to compute
|
| +** the limit and offset. If there is no limit and/or offset, then
|
| +** iLimit and iOffset are negative.
|
| +**
|
| +** This routine changes the values of iLimit and iOffset only if
|
| +** a limit or offset is defined by pLimit and pOffset. iLimit and
|
| +** iOffset should have been preset to appropriate default values
|
| +** (usually but not always -1) prior to calling this routine.
|
| +** Only if pLimit!=0 or pOffset!=0 do the limit registers get
|
| +** redefined. The UNION ALL operator uses this property to force
|
| +** the reuse of the same limit and offset registers across multiple
|
| +** SELECT statements.
|
| +*/
|
| +static void computeLimitRegisters(Parse *pParse, Select *p, int iBreak){
|
| + Vdbe *v = 0;
|
| + int iLimit = 0;
|
| + int iOffset;
|
| + int addr1, n;
|
| + if( p->iLimit ) return;
|
| +
|
| + /*
|
| + ** "LIMIT -1" always shows all rows. There is some
|
| + ** contraversy about what the correct behavior should be.
|
| + ** The current implementation interprets "LIMIT 0" to mean
|
| + ** no rows.
|
| + */
|
| + sqlite3ExprCacheClear(pParse);
|
| + assert( p->pOffset==0 || p->pLimit!=0 );
|
| + if( p->pLimit ){
|
| + p->iLimit = iLimit = ++pParse->nMem;
|
| + v = sqlite3GetVdbe(pParse);
|
| + if( NEVER(v==0) ) return; /* VDBE should have already been allocated */
|
| + if( sqlite3ExprIsInteger(p->pLimit, &n) ){
|
| + sqlite3VdbeAddOp2(v, OP_Integer, n, iLimit);
|
| + VdbeComment((v, "LIMIT counter"));
|
| + if( n==0 ){
|
| + sqlite3VdbeAddOp2(v, OP_Goto, 0, iBreak);
|
| + }else{
|
| + if( p->nSelectRow > (double)n ) p->nSelectRow = (double)n;
|
| + }
|
| + }else{
|
| + sqlite3ExprCode(pParse, p->pLimit, iLimit);
|
| + sqlite3VdbeAddOp1(v, OP_MustBeInt, iLimit);
|
| + VdbeComment((v, "LIMIT counter"));
|
| + sqlite3VdbeAddOp2(v, OP_IfZero, iLimit, iBreak);
|
| + }
|
| + if( p->pOffset ){
|
| + p->iOffset = iOffset = ++pParse->nMem;
|
| + pParse->nMem++; /* Allocate an extra register for limit+offset */
|
| + sqlite3ExprCode(pParse, p->pOffset, iOffset);
|
| + sqlite3VdbeAddOp1(v, OP_MustBeInt, iOffset);
|
| + VdbeComment((v, "OFFSET counter"));
|
| + addr1 = sqlite3VdbeAddOp1(v, OP_IfPos, iOffset);
|
| + sqlite3VdbeAddOp2(v, OP_Integer, 0, iOffset);
|
| + sqlite3VdbeJumpHere(v, addr1);
|
| + sqlite3VdbeAddOp3(v, OP_Add, iLimit, iOffset, iOffset+1);
|
| + VdbeComment((v, "LIMIT+OFFSET"));
|
| + addr1 = sqlite3VdbeAddOp1(v, OP_IfPos, iLimit);
|
| + sqlite3VdbeAddOp2(v, OP_Integer, -1, iOffset+1);
|
| + sqlite3VdbeJumpHere(v, addr1);
|
| + }
|
| + }
|
| +}
|
| +
|
| +#ifndef SQLITE_OMIT_COMPOUND_SELECT
|
| +/*
|
| +** Return the appropriate collating sequence for the iCol-th column of
|
| +** the result set for the compound-select statement "p". Return NULL if
|
| +** the column has no default collating sequence.
|
| +**
|
| +** The collating sequence for the compound select is taken from the
|
| +** left-most term of the select that has a collating sequence.
|
| +*/
|
| +static CollSeq *multiSelectCollSeq(Parse *pParse, Select *p, int iCol){
|
| + CollSeq *pRet;
|
| + if( p->pPrior ){
|
| + pRet = multiSelectCollSeq(pParse, p->pPrior, iCol);
|
| + }else{
|
| + pRet = 0;
|
| + }
|
| + assert( iCol>=0 );
|
| + if( pRet==0 && iCol<p->pEList->nExpr ){
|
| + pRet = sqlite3ExprCollSeq(pParse, p->pEList->a[iCol].pExpr);
|
| + }
|
| + return pRet;
|
| +}
|
| +#endif /* SQLITE_OMIT_COMPOUND_SELECT */
|
| +
|
| +/* Forward reference */
|
| +static int multiSelectOrderBy(
|
| + Parse *pParse, /* Parsing context */
|
| + Select *p, /* The right-most of SELECTs to be coded */
|
| + SelectDest *pDest /* What to do with query results */
|
| +);
|
| +
|
| +
|
| +#ifndef SQLITE_OMIT_COMPOUND_SELECT
|
| +/*
|
| +** This routine is called to process a compound query form from
|
| +** two or more separate queries using UNION, UNION ALL, EXCEPT, or
|
| +** INTERSECT
|
| +**
|
| +** "p" points to the right-most of the two queries. the query on the
|
| +** left is p->pPrior. The left query could also be a compound query
|
| +** in which case this routine will be called recursively.
|
| +**
|
| +** The results of the total query are to be written into a destination
|
| +** of type eDest with parameter iParm.
|
| +**
|
| +** Example 1: Consider a three-way compound SQL statement.
|
| +**
|
| +** SELECT a FROM t1 UNION SELECT b FROM t2 UNION SELECT c FROM t3
|
| +**
|
| +** This statement is parsed up as follows:
|
| +**
|
| +** SELECT c FROM t3
|
| +** |
|
| +** `-----> SELECT b FROM t2
|
| +** |
|
| +** `------> SELECT a FROM t1
|
| +**
|
| +** The arrows in the diagram above represent the Select.pPrior pointer.
|
| +** So if this routine is called with p equal to the t3 query, then
|
| +** pPrior will be the t2 query. p->op will be TK_UNION in this case.
|
| +**
|
| +** Notice that because of the way SQLite parses compound SELECTs, the
|
| +** individual selects always group from left to right.
|
| +*/
|
| +static int multiSelect(
|
| + Parse *pParse, /* Parsing context */
|
| + Select *p, /* The right-most of SELECTs to be coded */
|
| + SelectDest *pDest /* What to do with query results */
|
| +){
|
| + int rc = SQLITE_OK; /* Success code from a subroutine */
|
| + Select *pPrior; /* Another SELECT immediately to our left */
|
| + Vdbe *v; /* Generate code to this VDBE */
|
| + SelectDest dest; /* Alternative data destination */
|
| + Select *pDelete = 0; /* Chain of simple selects to delete */
|
| + sqlite3 *db; /* Database connection */
|
| +#ifndef SQLITE_OMIT_EXPLAIN
|
| + int iSub1; /* EQP id of left-hand query */
|
| + int iSub2; /* EQP id of right-hand query */
|
| +#endif
|
| +
|
| + /* Make sure there is no ORDER BY or LIMIT clause on prior SELECTs. Only
|
| + ** the last (right-most) SELECT in the series may have an ORDER BY or LIMIT.
|
| + */
|
| + assert( p && p->pPrior ); /* Calling function guarantees this much */
|
| + db = pParse->db;
|
| + pPrior = p->pPrior;
|
| + assert( pPrior->pRightmost!=pPrior );
|
| + assert( pPrior->pRightmost==p->pRightmost );
|
| + dest = *pDest;
|
| + if( pPrior->pOrderBy ){
|
| + sqlite3ErrorMsg(pParse,"ORDER BY clause should come after %s not before",
|
| + selectOpName(p->op));
|
| + rc = 1;
|
| + goto multi_select_end;
|
| + }
|
| + if( pPrior->pLimit ){
|
| + sqlite3ErrorMsg(pParse,"LIMIT clause should come after %s not before",
|
| + selectOpName(p->op));
|
| + rc = 1;
|
| + goto multi_select_end;
|
| + }
|
| +
|
| + v = sqlite3GetVdbe(pParse);
|
| + assert( v!=0 ); /* The VDBE already created by calling function */
|
| +
|
| + /* Create the destination temporary table if necessary
|
| + */
|
| + if( dest.eDest==SRT_EphemTab ){
|
| + assert( p->pEList );
|
| + sqlite3VdbeAddOp2(v, OP_OpenEphemeral, dest.iParm, p->pEList->nExpr);
|
| + sqlite3VdbeChangeP5(v, BTREE_UNORDERED);
|
| + dest.eDest = SRT_Table;
|
| + }
|
| +
|
| + /* Make sure all SELECTs in the statement have the same number of elements
|
| + ** in their result sets.
|
| + */
|
| + assert( p->pEList && pPrior->pEList );
|
| + if( p->pEList->nExpr!=pPrior->pEList->nExpr ){
|
| + sqlite3ErrorMsg(pParse, "SELECTs to the left and right of %s"
|
| + " do not have the same number of result columns", selectOpName(p->op));
|
| + rc = 1;
|
| + goto multi_select_end;
|
| + }
|
| +
|
| + /* Compound SELECTs that have an ORDER BY clause are handled separately.
|
| + */
|
| + if( p->pOrderBy ){
|
| + return multiSelectOrderBy(pParse, p, pDest);
|
| + }
|
| +
|
| + /* Generate code for the left and right SELECT statements.
|
| + */
|
| + switch( p->op ){
|
| + case TK_ALL: {
|
| + int addr = 0;
|
| + int nLimit;
|
| + assert( !pPrior->pLimit );
|
| + pPrior->pLimit = p->pLimit;
|
| + pPrior->pOffset = p->pOffset;
|
| + explainSetInteger(iSub1, pParse->iNextSelectId);
|
| + rc = sqlite3Select(pParse, pPrior, &dest);
|
| + p->pLimit = 0;
|
| + p->pOffset = 0;
|
| + if( rc ){
|
| + goto multi_select_end;
|
| + }
|
| + p->pPrior = 0;
|
| + p->iLimit = pPrior->iLimit;
|
| + p->iOffset = pPrior->iOffset;
|
| + if( p->iLimit ){
|
| + addr = sqlite3VdbeAddOp1(v, OP_IfZero, p->iLimit);
|
| + VdbeComment((v, "Jump ahead if LIMIT reached"));
|
| + }
|
| + explainSetInteger(iSub2, pParse->iNextSelectId);
|
| + rc = sqlite3Select(pParse, p, &dest);
|
| + testcase( rc!=SQLITE_OK );
|
| + pDelete = p->pPrior;
|
| + p->pPrior = pPrior;
|
| + p->nSelectRow += pPrior->nSelectRow;
|
| + if( pPrior->pLimit
|
| + && sqlite3ExprIsInteger(pPrior->pLimit, &nLimit)
|
| + && p->nSelectRow > (double)nLimit
|
| + ){
|
| + p->nSelectRow = (double)nLimit;
|
| + }
|
| + if( addr ){
|
| + sqlite3VdbeJumpHere(v, addr);
|
| + }
|
| + break;
|
| + }
|
| + case TK_EXCEPT:
|
| + case TK_UNION: {
|
| + int unionTab; /* Cursor number of the temporary table holding result */
|
| + u8 op = 0; /* One of the SRT_ operations to apply to self */
|
| + int priorOp; /* The SRT_ operation to apply to prior selects */
|
| + Expr *pLimit, *pOffset; /* Saved values of p->nLimit and p->nOffset */
|
| + int addr;
|
| + SelectDest uniondest;
|
| +
|
| + testcase( p->op==TK_EXCEPT );
|
| + testcase( p->op==TK_UNION );
|
| + priorOp = SRT_Union;
|
| + if( dest.eDest==priorOp && ALWAYS(!p->pLimit &&!p->pOffset) ){
|
| + /* We can reuse a temporary table generated by a SELECT to our
|
| + ** right.
|
| + */
|
| + assert( p->pRightmost!=p ); /* Can only happen for leftward elements
|
| + ** of a 3-way or more compound */
|
| + assert( p->pLimit==0 ); /* Not allowed on leftward elements */
|
| + assert( p->pOffset==0 ); /* Not allowed on leftward elements */
|
| + unionTab = dest.iParm;
|
| + }else{
|
| + /* We will need to create our own temporary table to hold the
|
| + ** intermediate results.
|
| + */
|
| + unionTab = pParse->nTab++;
|
| + assert( p->pOrderBy==0 );
|
| + addr = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, unionTab, 0);
|
| + assert( p->addrOpenEphm[0] == -1 );
|
| + p->addrOpenEphm[0] = addr;
|
| + p->pRightmost->selFlags |= SF_UsesEphemeral;
|
| + assert( p->pEList );
|
| + }
|
| +
|
| + /* Code the SELECT statements to our left
|
| + */
|
| + assert( !pPrior->pOrderBy );
|
| + sqlite3SelectDestInit(&uniondest, priorOp, unionTab);
|
| + explainSetInteger(iSub1, pParse->iNextSelectId);
|
| + rc = sqlite3Select(pParse, pPrior, &uniondest);
|
| + if( rc ){
|
| + goto multi_select_end;
|
| + }
|
| +
|
| + /* Code the current SELECT statement
|
| + */
|
| + if( p->op==TK_EXCEPT ){
|
| + op = SRT_Except;
|
| + }else{
|
| + assert( p->op==TK_UNION );
|
| + op = SRT_Union;
|
| + }
|
| + p->pPrior = 0;
|
| + pLimit = p->pLimit;
|
| + p->pLimit = 0;
|
| + pOffset = p->pOffset;
|
| + p->pOffset = 0;
|
| + uniondest.eDest = op;
|
| + explainSetInteger(iSub2, pParse->iNextSelectId);
|
| + rc = sqlite3Select(pParse, p, &uniondest);
|
| + testcase( rc!=SQLITE_OK );
|
| + /* Query flattening in sqlite3Select() might refill p->pOrderBy.
|
| + ** Be sure to delete p->pOrderBy, therefore, to avoid a memory leak. */
|
| + sqlite3ExprListDelete(db, p->pOrderBy);
|
| + pDelete = p->pPrior;
|
| + p->pPrior = pPrior;
|
| + p->pOrderBy = 0;
|
| + if( p->op==TK_UNION ) p->nSelectRow += pPrior->nSelectRow;
|
| + sqlite3ExprDelete(db, p->pLimit);
|
| + p->pLimit = pLimit;
|
| + p->pOffset = pOffset;
|
| + p->iLimit = 0;
|
| + p->iOffset = 0;
|
| +
|
| + /* Convert the data in the temporary table into whatever form
|
| + ** it is that we currently need.
|
| + */
|
| + assert( unionTab==dest.iParm || dest.eDest!=priorOp );
|
| + if( dest.eDest!=priorOp ){
|
| + int iCont, iBreak, iStart;
|
| + assert( p->pEList );
|
| + if( dest.eDest==SRT_Output ){
|
| + Select *pFirst = p;
|
| + while( pFirst->pPrior ) pFirst = pFirst->pPrior;
|
| + generateColumnNames(pParse, 0, pFirst->pEList);
|
| + }
|
| + iBreak = sqlite3VdbeMakeLabel(v);
|
| + iCont = sqlite3VdbeMakeLabel(v);
|
| + computeLimitRegisters(pParse, p, iBreak);
|
| + sqlite3VdbeAddOp2(v, OP_Rewind, unionTab, iBreak);
|
| + iStart = sqlite3VdbeCurrentAddr(v);
|
| + selectInnerLoop(pParse, p, p->pEList, unionTab, p->pEList->nExpr,
|
| + 0, -1, &dest, iCont, iBreak);
|
| + sqlite3VdbeResolveLabel(v, iCont);
|
| + sqlite3VdbeAddOp2(v, OP_Next, unionTab, iStart);
|
| + sqlite3VdbeResolveLabel(v, iBreak);
|
| + sqlite3VdbeAddOp2(v, OP_Close, unionTab, 0);
|
| + }
|
| + break;
|
| + }
|
| + default: assert( p->op==TK_INTERSECT ); {
|
| + int tab1, tab2;
|
| + int iCont, iBreak, iStart;
|
| + Expr *pLimit, *pOffset;
|
| + int addr;
|
| + SelectDest intersectdest;
|
| + int r1;
|
| +
|
| + /* INTERSECT is different from the others since it requires
|
| + ** two temporary tables. Hence it has its own case. Begin
|
| + ** by allocating the tables we will need.
|
| + */
|
| + tab1 = pParse->nTab++;
|
| + tab2 = pParse->nTab++;
|
| + assert( p->pOrderBy==0 );
|
| +
|
| + addr = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, tab1, 0);
|
| + assert( p->addrOpenEphm[0] == -1 );
|
| + p->addrOpenEphm[0] = addr;
|
| + p->pRightmost->selFlags |= SF_UsesEphemeral;
|
| + assert( p->pEList );
|
| +
|
| + /* Code the SELECTs to our left into temporary table "tab1".
|
| + */
|
| + sqlite3SelectDestInit(&intersectdest, SRT_Union, tab1);
|
| + explainSetInteger(iSub1, pParse->iNextSelectId);
|
| + rc = sqlite3Select(pParse, pPrior, &intersectdest);
|
| + if( rc ){
|
| + goto multi_select_end;
|
| + }
|
| +
|
| + /* Code the current SELECT into temporary table "tab2"
|
| + */
|
| + addr = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, tab2, 0);
|
| + assert( p->addrOpenEphm[1] == -1 );
|
| + p->addrOpenEphm[1] = addr;
|
| + p->pPrior = 0;
|
| + pLimit = p->pLimit;
|
| + p->pLimit = 0;
|
| + pOffset = p->pOffset;
|
| + p->pOffset = 0;
|
| + intersectdest.iParm = tab2;
|
| + explainSetInteger(iSub2, pParse->iNextSelectId);
|
| + rc = sqlite3Select(pParse, p, &intersectdest);
|
| + testcase( rc!=SQLITE_OK );
|
| + pDelete = p->pPrior;
|
| + p->pPrior = pPrior;
|
| + if( p->nSelectRow>pPrior->nSelectRow ) p->nSelectRow = pPrior->nSelectRow;
|
| + sqlite3ExprDelete(db, p->pLimit);
|
| + p->pLimit = pLimit;
|
| + p->pOffset = pOffset;
|
| +
|
| + /* Generate code to take the intersection of the two temporary
|
| + ** tables.
|
| + */
|
| + assert( p->pEList );
|
| + if( dest.eDest==SRT_Output ){
|
| + Select *pFirst = p;
|
| + while( pFirst->pPrior ) pFirst = pFirst->pPrior;
|
| + generateColumnNames(pParse, 0, pFirst->pEList);
|
| + }
|
| + iBreak = sqlite3VdbeMakeLabel(v);
|
| + iCont = sqlite3VdbeMakeLabel(v);
|
| + computeLimitRegisters(pParse, p, iBreak);
|
| + sqlite3VdbeAddOp2(v, OP_Rewind, tab1, iBreak);
|
| + r1 = sqlite3GetTempReg(pParse);
|
| + iStart = sqlite3VdbeAddOp2(v, OP_RowKey, tab1, r1);
|
| + sqlite3VdbeAddOp4Int(v, OP_NotFound, tab2, iCont, r1, 0);
|
| + sqlite3ReleaseTempReg(pParse, r1);
|
| + selectInnerLoop(pParse, p, p->pEList, tab1, p->pEList->nExpr,
|
| + 0, -1, &dest, iCont, iBreak);
|
| + sqlite3VdbeResolveLabel(v, iCont);
|
| + sqlite3VdbeAddOp2(v, OP_Next, tab1, iStart);
|
| + sqlite3VdbeResolveLabel(v, iBreak);
|
| + sqlite3VdbeAddOp2(v, OP_Close, tab2, 0);
|
| + sqlite3VdbeAddOp2(v, OP_Close, tab1, 0);
|
| + break;
|
| + }
|
| + }
|
| +
|
| + explainComposite(pParse, p->op, iSub1, iSub2, p->op!=TK_ALL);
|
| +
|
| + /* Compute collating sequences used by
|
| + ** temporary tables needed to implement the compound select.
|
| + ** Attach the KeyInfo structure to all temporary tables.
|
| + **
|
| + ** This section is run by the right-most SELECT statement only.
|
| + ** SELECT statements to the left always skip this part. The right-most
|
| + ** SELECT might also skip this part if it has no ORDER BY clause and
|
| + ** no temp tables are required.
|
| + */
|
| + if( p->selFlags & SF_UsesEphemeral ){
|
| + int i; /* Loop counter */
|
| + KeyInfo *pKeyInfo; /* Collating sequence for the result set */
|
| + Select *pLoop; /* For looping through SELECT statements */
|
| + CollSeq **apColl; /* For looping through pKeyInfo->aColl[] */
|
| + int nCol; /* Number of columns in result set */
|
| +
|
| + assert( p->pRightmost==p );
|
| + nCol = p->pEList->nExpr;
|
| + pKeyInfo = sqlite3DbMallocZero(db,
|
| + sizeof(*pKeyInfo)+nCol*(sizeof(CollSeq*) + 1));
|
| + if( !pKeyInfo ){
|
| + rc = SQLITE_NOMEM;
|
| + goto multi_select_end;
|
| + }
|
| +
|
| + pKeyInfo->enc = ENC(db);
|
| + pKeyInfo->nField = (u16)nCol;
|
| +
|
| + for(i=0, apColl=pKeyInfo->aColl; i<nCol; i++, apColl++){
|
| + *apColl = multiSelectCollSeq(pParse, p, i);
|
| + if( 0==*apColl ){
|
| + *apColl = db->pDfltColl;
|
| + }
|
| + }
|
| +
|
| + for(pLoop=p; pLoop; pLoop=pLoop->pPrior){
|
| + for(i=0; i<2; i++){
|
| + int addr = pLoop->addrOpenEphm[i];
|
| + if( addr<0 ){
|
| + /* If [0] is unused then [1] is also unused. So we can
|
| + ** always safely abort as soon as the first unused slot is found */
|
| + assert( pLoop->addrOpenEphm[1]<0 );
|
| + break;
|
| + }
|
| + sqlite3VdbeChangeP2(v, addr, nCol);
|
| + sqlite3VdbeChangeP4(v, addr, (char*)pKeyInfo, P4_KEYINFO);
|
| + pLoop->addrOpenEphm[i] = -1;
|
| + }
|
| + }
|
| + sqlite3DbFree(db, pKeyInfo);
|
| + }
|
| +
|
| +multi_select_end:
|
| + pDest->iMem = dest.iMem;
|
| + pDest->nMem = dest.nMem;
|
| + sqlite3SelectDelete(db, pDelete);
|
| + return rc;
|
| +}
|
| +#endif /* SQLITE_OMIT_COMPOUND_SELECT */
|
| +
|
| +/*
|
| +** Code an output subroutine for a coroutine implementation of a
|
| +** SELECT statment.
|
| +**
|
| +** The data to be output is contained in pIn->iMem. There are
|
| +** pIn->nMem columns to be output. pDest is where the output should
|
| +** be sent.
|
| +**
|
| +** regReturn is the number of the register holding the subroutine
|
| +** return address.
|
| +**
|
| +** If regPrev>0 then it is the first register in a vector that
|
| +** records the previous output. mem[regPrev] is a flag that is false
|
| +** if there has been no previous output. If regPrev>0 then code is
|
| +** generated to suppress duplicates. pKeyInfo is used for comparing
|
| +** keys.
|
| +**
|
| +** If the LIMIT found in p->iLimit is reached, jump immediately to
|
| +** iBreak.
|
| +*/
|
| +static int generateOutputSubroutine(
|
| + Parse *pParse, /* Parsing context */
|
| + Select *p, /* The SELECT statement */
|
| + SelectDest *pIn, /* Coroutine supplying data */
|
| + SelectDest *pDest, /* Where to send the data */
|
| + int regReturn, /* The return address register */
|
| + int regPrev, /* Previous result register. No uniqueness if 0 */
|
| + KeyInfo *pKeyInfo, /* For comparing with previous entry */
|
| + int p4type, /* The p4 type for pKeyInfo */
|
| + int iBreak /* Jump here if we hit the LIMIT */
|
| +){
|
| + Vdbe *v = pParse->pVdbe;
|
| + int iContinue;
|
| + int addr;
|
| +
|
| + addr = sqlite3VdbeCurrentAddr(v);
|
| + iContinue = sqlite3VdbeMakeLabel(v);
|
| +
|
| + /* Suppress duplicates for UNION, EXCEPT, and INTERSECT
|
| + */
|
| + if( regPrev ){
|
| + int j1, j2;
|
| + j1 = sqlite3VdbeAddOp1(v, OP_IfNot, regPrev);
|
| + j2 = sqlite3VdbeAddOp4(v, OP_Compare, pIn->iMem, regPrev+1, pIn->nMem,
|
| + (char*)pKeyInfo, p4type);
|
| + sqlite3VdbeAddOp3(v, OP_Jump, j2+2, iContinue, j2+2);
|
| + sqlite3VdbeJumpHere(v, j1);
|
| + sqlite3ExprCodeCopy(pParse, pIn->iMem, regPrev+1, pIn->nMem);
|
| + sqlite3VdbeAddOp2(v, OP_Integer, 1, regPrev);
|
| + }
|
| + if( pParse->db->mallocFailed ) return 0;
|
| +
|
| + /* Suppress the the first OFFSET entries if there is an OFFSET clause
|
| + */
|
| + codeOffset(v, p, iContinue);
|
| +
|
| + switch( pDest->eDest ){
|
| + /* Store the result as data using a unique key.
|
| + */
|
| + case SRT_Table:
|
| + case SRT_EphemTab: {
|
| + int r1 = sqlite3GetTempReg(pParse);
|
| + int r2 = sqlite3GetTempReg(pParse);
|
| + testcase( pDest->eDest==SRT_Table );
|
| + testcase( pDest->eDest==SRT_EphemTab );
|
| + sqlite3VdbeAddOp3(v, OP_MakeRecord, pIn->iMem, pIn->nMem, r1);
|
| + sqlite3VdbeAddOp2(v, OP_NewRowid, pDest->iParm, r2);
|
| + sqlite3VdbeAddOp3(v, OP_Insert, pDest->iParm, r1, r2);
|
| + sqlite3VdbeChangeP5(v, OPFLAG_APPEND);
|
| + sqlite3ReleaseTempReg(pParse, r2);
|
| + sqlite3ReleaseTempReg(pParse, r1);
|
| + break;
|
| + }
|
| +
|
| +#ifndef SQLITE_OMIT_SUBQUERY
|
| + /* If we are creating a set for an "expr IN (SELECT ...)" construct,
|
| + ** then there should be a single item on the stack. Write this
|
| + ** item into the set table with bogus data.
|
| + */
|
| + case SRT_Set: {
|
| + int r1;
|
| + assert( pIn->nMem==1 );
|
| + p->affinity =
|
| + sqlite3CompareAffinity(p->pEList->a[0].pExpr, pDest->affinity);
|
| + r1 = sqlite3GetTempReg(pParse);
|
| + sqlite3VdbeAddOp4(v, OP_MakeRecord, pIn->iMem, 1, r1, &p->affinity, 1);
|
| + sqlite3ExprCacheAffinityChange(pParse, pIn->iMem, 1);
|
| + sqlite3VdbeAddOp2(v, OP_IdxInsert, pDest->iParm, r1);
|
| + sqlite3ReleaseTempReg(pParse, r1);
|
| + break;
|
| + }
|
| +
|
| +#if 0 /* Never occurs on an ORDER BY query */
|
| + /* If any row exist in the result set, record that fact and abort.
|
| + */
|
| + case SRT_Exists: {
|
| + sqlite3VdbeAddOp2(v, OP_Integer, 1, pDest->iParm);
|
| + /* The LIMIT clause will terminate the loop for us */
|
| + break;
|
| + }
|
| +#endif
|
| +
|
| + /* If this is a scalar select that is part of an expression, then
|
| + ** store the results in the appropriate memory cell and break out
|
| + ** of the scan loop.
|
| + */
|
| + case SRT_Mem: {
|
| + assert( pIn->nMem==1 );
|
| + sqlite3ExprCodeMove(pParse, pIn->iMem, pDest->iParm, 1);
|
| + /* The LIMIT clause will jump out of the loop for us */
|
| + break;
|
| + }
|
| +#endif /* #ifndef SQLITE_OMIT_SUBQUERY */
|
| +
|
| + /* The results are stored in a sequence of registers
|
| + ** starting at pDest->iMem. Then the co-routine yields.
|
| + */
|
| + case SRT_Coroutine: {
|
| + if( pDest->iMem==0 ){
|
| + pDest->iMem = sqlite3GetTempRange(pParse, pIn->nMem);
|
| + pDest->nMem = pIn->nMem;
|
| + }
|
| + sqlite3ExprCodeMove(pParse, pIn->iMem, pDest->iMem, pDest->nMem);
|
| + sqlite3VdbeAddOp1(v, OP_Yield, pDest->iParm);
|
| + break;
|
| + }
|
| +
|
| + /* If none of the above, then the result destination must be
|
| + ** SRT_Output. This routine is never called with any other
|
| + ** destination other than the ones handled above or SRT_Output.
|
| + **
|
| + ** For SRT_Output, results are stored in a sequence of registers.
|
| + ** Then the OP_ResultRow opcode is used to cause sqlite3_step() to
|
| + ** return the next row of result.
|
| + */
|
| + default: {
|
| + assert( pDest->eDest==SRT_Output );
|
| + sqlite3VdbeAddOp2(v, OP_ResultRow, pIn->iMem, pIn->nMem);
|
| + sqlite3ExprCacheAffinityChange(pParse, pIn->iMem, pIn->nMem);
|
| + break;
|
| + }
|
| + }
|
| +
|
| + /* Jump to the end of the loop if the LIMIT is reached.
|
| + */
|
| + if( p->iLimit ){
|
| + sqlite3VdbeAddOp3(v, OP_IfZero, p->iLimit, iBreak, -1);
|
| + }
|
| +
|
| + /* Generate the subroutine return
|
| + */
|
| + sqlite3VdbeResolveLabel(v, iContinue);
|
| + sqlite3VdbeAddOp1(v, OP_Return, regReturn);
|
| +
|
| + return addr;
|
| +}
|
| +
|
| +/*
|
| +** Alternative compound select code generator for cases when there
|
| +** is an ORDER BY clause.
|
| +**
|
| +** We assume a query of the following form:
|
| +**
|
| +** <selectA> <operator> <selectB> ORDER BY <orderbylist>
|
| +**
|
| +** <operator> is one of UNION ALL, UNION, EXCEPT, or INTERSECT. The idea
|
| +** is to code both <selectA> and <selectB> with the ORDER BY clause as
|
| +** co-routines. Then run the co-routines in parallel and merge the results
|
| +** into the output. In addition to the two coroutines (called selectA and
|
| +** selectB) there are 7 subroutines:
|
| +**
|
| +** outA: Move the output of the selectA coroutine into the output
|
| +** of the compound query.
|
| +**
|
| +** outB: Move the output of the selectB coroutine into the output
|
| +** of the compound query. (Only generated for UNION and
|
| +** UNION ALL. EXCEPT and INSERTSECT never output a row that
|
| +** appears only in B.)
|
| +**
|
| +** AltB: Called when there is data from both coroutines and A<B.
|
| +**
|
| +** AeqB: Called when there is data from both coroutines and A==B.
|
| +**
|
| +** AgtB: Called when there is data from both coroutines and A>B.
|
| +**
|
| +** EofA: Called when data is exhausted from selectA.
|
| +**
|
| +** EofB: Called when data is exhausted from selectB.
|
| +**
|
| +** The implementation of the latter five subroutines depend on which
|
| +** <operator> is used:
|
| +**
|
| +**
|
| +** UNION ALL UNION EXCEPT INTERSECT
|
| +** ------------- ----------------- -------------- -----------------
|
| +** AltB: outA, nextA outA, nextA outA, nextA nextA
|
| +**
|
| +** AeqB: outA, nextA nextA nextA outA, nextA
|
| +**
|
| +** AgtB: outB, nextB outB, nextB nextB nextB
|
| +**
|
| +** EofA: outB, nextB outB, nextB halt halt
|
| +**
|
| +** EofB: outA, nextA outA, nextA outA, nextA halt
|
| +**
|
| +** In the AltB, AeqB, and AgtB subroutines, an EOF on A following nextA
|
| +** causes an immediate jump to EofA and an EOF on B following nextB causes
|
| +** an immediate jump to EofB. Within EofA and EofB, and EOF on entry or
|
| +** following nextX causes a jump to the end of the select processing.
|
| +**
|
| +** Duplicate removal in the UNION, EXCEPT, and INTERSECT cases is handled
|
| +** within the output subroutine. The regPrev register set holds the previously
|
| +** output value. A comparison is made against this value and the output
|
| +** is skipped if the next results would be the same as the previous.
|
| +**
|
| +** The implementation plan is to implement the two coroutines and seven
|
| +** subroutines first, then put the control logic at the bottom. Like this:
|
| +**
|
| +** goto Init
|
| +** coA: coroutine for left query (A)
|
| +** coB: coroutine for right query (B)
|
| +** outA: output one row of A
|
| +** outB: output one row of B (UNION and UNION ALL only)
|
| +** EofA: ...
|
| +** EofB: ...
|
| +** AltB: ...
|
| +** AeqB: ...
|
| +** AgtB: ...
|
| +** Init: initialize coroutine registers
|
| +** yield coA
|
| +** if eof(A) goto EofA
|
| +** yield coB
|
| +** if eof(B) goto EofB
|
| +** Cmpr: Compare A, B
|
| +** Jump AltB, AeqB, AgtB
|
| +** End: ...
|
| +**
|
| +** We call AltB, AeqB, AgtB, EofA, and EofB "subroutines" but they are not
|
| +** actually called using Gosub and they do not Return. EofA and EofB loop
|
| +** until all data is exhausted then jump to the "end" labe. AltB, AeqB,
|
| +** and AgtB jump to either L2 or to one of EofA or EofB.
|
| +*/
|
| +#ifndef SQLITE_OMIT_COMPOUND_SELECT
|
| +static int multiSelectOrderBy(
|
| + Parse *pParse, /* Parsing context */
|
| + Select *p, /* The right-most of SELECTs to be coded */
|
| + SelectDest *pDest /* What to do with query results */
|
| +){
|
| + int i, j; /* Loop counters */
|
| + Select *pPrior; /* Another SELECT immediately to our left */
|
| + Vdbe *v; /* Generate code to this VDBE */
|
| + SelectDest destA; /* Destination for coroutine A */
|
| + SelectDest destB; /* Destination for coroutine B */
|
| + int regAddrA; /* Address register for select-A coroutine */
|
| + int regEofA; /* Flag to indicate when select-A is complete */
|
| + int regAddrB; /* Address register for select-B coroutine */
|
| + int regEofB; /* Flag to indicate when select-B is complete */
|
| + int addrSelectA; /* Address of the select-A coroutine */
|
| + int addrSelectB; /* Address of the select-B coroutine */
|
| + int regOutA; /* Address register for the output-A subroutine */
|
| + int regOutB; /* Address register for the output-B subroutine */
|
| + int addrOutA; /* Address of the output-A subroutine */
|
| + int addrOutB = 0; /* Address of the output-B subroutine */
|
| + int addrEofA; /* Address of the select-A-exhausted subroutine */
|
| + int addrEofB; /* Address of the select-B-exhausted subroutine */
|
| + int addrAltB; /* Address of the A<B subroutine */
|
| + int addrAeqB; /* Address of the A==B subroutine */
|
| + int addrAgtB; /* Address of the A>B subroutine */
|
| + int regLimitA; /* Limit register for select-A */
|
| + int regLimitB; /* Limit register for select-A */
|
| + int regPrev; /* A range of registers to hold previous output */
|
| + int savedLimit; /* Saved value of p->iLimit */
|
| + int savedOffset; /* Saved value of p->iOffset */
|
| + int labelCmpr; /* Label for the start of the merge algorithm */
|
| + int labelEnd; /* Label for the end of the overall SELECT stmt */
|
| + int j1; /* Jump instructions that get retargetted */
|
| + int op; /* One of TK_ALL, TK_UNION, TK_EXCEPT, TK_INTERSECT */
|
| + KeyInfo *pKeyDup = 0; /* Comparison information for duplicate removal */
|
| + KeyInfo *pKeyMerge; /* Comparison information for merging rows */
|
| + sqlite3 *db; /* Database connection */
|
| + ExprList *pOrderBy; /* The ORDER BY clause */
|
| + int nOrderBy; /* Number of terms in the ORDER BY clause */
|
| + int *aPermute; /* Mapping from ORDER BY terms to result set columns */
|
| +#ifndef SQLITE_OMIT_EXPLAIN
|
| + int iSub1; /* EQP id of left-hand query */
|
| + int iSub2; /* EQP id of right-hand query */
|
| +#endif
|
| +
|
| + assert( p->pOrderBy!=0 );
|
| + assert( pKeyDup==0 ); /* "Managed" code needs this. Ticket #3382. */
|
| + db = pParse->db;
|
| + v = pParse->pVdbe;
|
| + assert( v!=0 ); /* Already thrown the error if VDBE alloc failed */
|
| + labelEnd = sqlite3VdbeMakeLabel(v);
|
| + labelCmpr = sqlite3VdbeMakeLabel(v);
|
| +
|
| +
|
| + /* Patch up the ORDER BY clause
|
| + */
|
| + op = p->op;
|
| + pPrior = p->pPrior;
|
| + assert( pPrior->pOrderBy==0 );
|
| + pOrderBy = p->pOrderBy;
|
| + assert( pOrderBy );
|
| + nOrderBy = pOrderBy->nExpr;
|
| +
|
| + /* For operators other than UNION ALL we have to make sure that
|
| + ** the ORDER BY clause covers every term of the result set. Add
|
| + ** terms to the ORDER BY clause as necessary.
|
| + */
|
| + if( op!=TK_ALL ){
|
| + for(i=1; db->mallocFailed==0 && i<=p->pEList->nExpr; i++){
|
| + struct ExprList_item *pItem;
|
| + for(j=0, pItem=pOrderBy->a; j<nOrderBy; j++, pItem++){
|
| + assert( pItem->iCol>0 );
|
| + if( pItem->iCol==i ) break;
|
| + }
|
| + if( j==nOrderBy ){
|
| + Expr *pNew = sqlite3Expr(db, TK_INTEGER, 0);
|
| + if( pNew==0 ) return SQLITE_NOMEM;
|
| + pNew->flags |= EP_IntValue;
|
| + pNew->u.iValue = i;
|
| + pOrderBy = sqlite3ExprListAppend(pParse, pOrderBy, pNew);
|
| + pOrderBy->a[nOrderBy++].iCol = (u16)i;
|
| + }
|
| + }
|
| + }
|
| +
|
| + /* Compute the comparison permutation and keyinfo that is used with
|
| + ** the permutation used to determine if the next
|
| + ** row of results comes from selectA or selectB. Also add explicit
|
| + ** collations to the ORDER BY clause terms so that when the subqueries
|
| + ** to the right and the left are evaluated, they use the correct
|
| + ** collation.
|
| + */
|
| + aPermute = sqlite3DbMallocRaw(db, sizeof(int)*nOrderBy);
|
| + if( aPermute ){
|
| + struct ExprList_item *pItem;
|
| + for(i=0, pItem=pOrderBy->a; i<nOrderBy; i++, pItem++){
|
| + assert( pItem->iCol>0 && pItem->iCol<=p->pEList->nExpr );
|
| + aPermute[i] = pItem->iCol - 1;
|
| + }
|
| + pKeyMerge =
|
| + sqlite3DbMallocRaw(db, sizeof(*pKeyMerge)+nOrderBy*(sizeof(CollSeq*)+1));
|
| + if( pKeyMerge ){
|
| + pKeyMerge->aSortOrder = (u8*)&pKeyMerge->aColl[nOrderBy];
|
| + pKeyMerge->nField = (u16)nOrderBy;
|
| + pKeyMerge->enc = ENC(db);
|
| + for(i=0; i<nOrderBy; i++){
|
| + CollSeq *pColl;
|
| + Expr *pTerm = pOrderBy->a[i].pExpr;
|
| + if( pTerm->flags & EP_ExpCollate ){
|
| + pColl = pTerm->pColl;
|
| + }else{
|
| + pColl = multiSelectCollSeq(pParse, p, aPermute[i]);
|
| + pTerm->flags |= EP_ExpCollate;
|
| + pTerm->pColl = pColl;
|
| + }
|
| + pKeyMerge->aColl[i] = pColl;
|
| + pKeyMerge->aSortOrder[i] = pOrderBy->a[i].sortOrder;
|
| + }
|
| + }
|
| + }else{
|
| + pKeyMerge = 0;
|
| + }
|
| +
|
| + /* Reattach the ORDER BY clause to the query.
|
| + */
|
| + p->pOrderBy = pOrderBy;
|
| + pPrior->pOrderBy = sqlite3ExprListDup(pParse->db, pOrderBy, 0);
|
| +
|
| + /* Allocate a range of temporary registers and the KeyInfo needed
|
| + ** for the logic that removes duplicate result rows when the
|
| + ** operator is UNION, EXCEPT, or INTERSECT (but not UNION ALL).
|
| + */
|
| + if( op==TK_ALL ){
|
| + regPrev = 0;
|
| + }else{
|
| + int nExpr = p->pEList->nExpr;
|
| + assert( nOrderBy>=nExpr || db->mallocFailed );
|
| + regPrev = sqlite3GetTempRange(pParse, nExpr+1);
|
| + sqlite3VdbeAddOp2(v, OP_Integer, 0, regPrev);
|
| + pKeyDup = sqlite3DbMallocZero(db,
|
| + sizeof(*pKeyDup) + nExpr*(sizeof(CollSeq*)+1) );
|
| + if( pKeyDup ){
|
| + pKeyDup->aSortOrder = (u8*)&pKeyDup->aColl[nExpr];
|
| + pKeyDup->nField = (u16)nExpr;
|
| + pKeyDup->enc = ENC(db);
|
| + for(i=0; i<nExpr; i++){
|
| + pKeyDup->aColl[i] = multiSelectCollSeq(pParse, p, i);
|
| + pKeyDup->aSortOrder[i] = 0;
|
| + }
|
| + }
|
| + }
|
| +
|
| + /* Separate the left and the right query from one another
|
| + */
|
| + p->pPrior = 0;
|
| + sqlite3ResolveOrderGroupBy(pParse, p, p->pOrderBy, "ORDER");
|
| + if( pPrior->pPrior==0 ){
|
| + sqlite3ResolveOrderGroupBy(pParse, pPrior, pPrior->pOrderBy, "ORDER");
|
| + }
|
| +
|
| + /* Compute the limit registers */
|
| + computeLimitRegisters(pParse, p, labelEnd);
|
| + if( p->iLimit && op==TK_ALL ){
|
| + regLimitA = ++pParse->nMem;
|
| + regLimitB = ++pParse->nMem;
|
| + sqlite3VdbeAddOp2(v, OP_Copy, p->iOffset ? p->iOffset+1 : p->iLimit,
|
| + regLimitA);
|
| + sqlite3VdbeAddOp2(v, OP_Copy, regLimitA, regLimitB);
|
| + }else{
|
| + regLimitA = regLimitB = 0;
|
| + }
|
| + sqlite3ExprDelete(db, p->pLimit);
|
| + p->pLimit = 0;
|
| + sqlite3ExprDelete(db, p->pOffset);
|
| + p->pOffset = 0;
|
| +
|
| + regAddrA = ++pParse->nMem;
|
| + regEofA = ++pParse->nMem;
|
| + regAddrB = ++pParse->nMem;
|
| + regEofB = ++pParse->nMem;
|
| + regOutA = ++pParse->nMem;
|
| + regOutB = ++pParse->nMem;
|
| + sqlite3SelectDestInit(&destA, SRT_Coroutine, regAddrA);
|
| + sqlite3SelectDestInit(&destB, SRT_Coroutine, regAddrB);
|
| +
|
| + /* Jump past the various subroutines and coroutines to the main
|
| + ** merge loop
|
| + */
|
| + j1 = sqlite3VdbeAddOp0(v, OP_Goto);
|
| + addrSelectA = sqlite3VdbeCurrentAddr(v);
|
| +
|
| +
|
| + /* Generate a coroutine to evaluate the SELECT statement to the
|
| + ** left of the compound operator - the "A" select.
|
| + */
|
| + VdbeNoopComment((v, "Begin coroutine for left SELECT"));
|
| + pPrior->iLimit = regLimitA;
|
| + explainSetInteger(iSub1, pParse->iNextSelectId);
|
| + sqlite3Select(pParse, pPrior, &destA);
|
| + sqlite3VdbeAddOp2(v, OP_Integer, 1, regEofA);
|
| + sqlite3VdbeAddOp1(v, OP_Yield, regAddrA);
|
| + VdbeNoopComment((v, "End coroutine for left SELECT"));
|
| +
|
| + /* Generate a coroutine to evaluate the SELECT statement on
|
| + ** the right - the "B" select
|
| + */
|
| + addrSelectB = sqlite3VdbeCurrentAddr(v);
|
| + VdbeNoopComment((v, "Begin coroutine for right SELECT"));
|
| + savedLimit = p->iLimit;
|
| + savedOffset = p->iOffset;
|
| + p->iLimit = regLimitB;
|
| + p->iOffset = 0;
|
| + explainSetInteger(iSub2, pParse->iNextSelectId);
|
| + sqlite3Select(pParse, p, &destB);
|
| + p->iLimit = savedLimit;
|
| + p->iOffset = savedOffset;
|
| + sqlite3VdbeAddOp2(v, OP_Integer, 1, regEofB);
|
| + sqlite3VdbeAddOp1(v, OP_Yield, regAddrB);
|
| + VdbeNoopComment((v, "End coroutine for right SELECT"));
|
| +
|
| + /* Generate a subroutine that outputs the current row of the A
|
| + ** select as the next output row of the compound select.
|
| + */
|
| + VdbeNoopComment((v, "Output routine for A"));
|
| + addrOutA = generateOutputSubroutine(pParse,
|
| + p, &destA, pDest, regOutA,
|
| + regPrev, pKeyDup, P4_KEYINFO_HANDOFF, labelEnd);
|
| +
|
| + /* Generate a subroutine that outputs the current row of the B
|
| + ** select as the next output row of the compound select.
|
| + */
|
| + if( op==TK_ALL || op==TK_UNION ){
|
| + VdbeNoopComment((v, "Output routine for B"));
|
| + addrOutB = generateOutputSubroutine(pParse,
|
| + p, &destB, pDest, regOutB,
|
| + regPrev, pKeyDup, P4_KEYINFO_STATIC, labelEnd);
|
| + }
|
| +
|
| + /* Generate a subroutine to run when the results from select A
|
| + ** are exhausted and only data in select B remains.
|
| + */
|
| + VdbeNoopComment((v, "eof-A subroutine"));
|
| + if( op==TK_EXCEPT || op==TK_INTERSECT ){
|
| + addrEofA = sqlite3VdbeAddOp2(v, OP_Goto, 0, labelEnd);
|
| + }else{
|
| + addrEofA = sqlite3VdbeAddOp2(v, OP_If, regEofB, labelEnd);
|
| + sqlite3VdbeAddOp2(v, OP_Gosub, regOutB, addrOutB);
|
| + sqlite3VdbeAddOp1(v, OP_Yield, regAddrB);
|
| + sqlite3VdbeAddOp2(v, OP_Goto, 0, addrEofA);
|
| + p->nSelectRow += pPrior->nSelectRow;
|
| + }
|
| +
|
| + /* Generate a subroutine to run when the results from select B
|
| + ** are exhausted and only data in select A remains.
|
| + */
|
| + if( op==TK_INTERSECT ){
|
| + addrEofB = addrEofA;
|
| + if( p->nSelectRow > pPrior->nSelectRow ) p->nSelectRow = pPrior->nSelectRow;
|
| + }else{
|
| + VdbeNoopComment((v, "eof-B subroutine"));
|
| + addrEofB = sqlite3VdbeAddOp2(v, OP_If, regEofA, labelEnd);
|
| + sqlite3VdbeAddOp2(v, OP_Gosub, regOutA, addrOutA);
|
| + sqlite3VdbeAddOp1(v, OP_Yield, regAddrA);
|
| + sqlite3VdbeAddOp2(v, OP_Goto, 0, addrEofB);
|
| + }
|
| +
|
| + /* Generate code to handle the case of A<B
|
| + */
|
| + VdbeNoopComment((v, "A-lt-B subroutine"));
|
| + addrAltB = sqlite3VdbeAddOp2(v, OP_Gosub, regOutA, addrOutA);
|
| + sqlite3VdbeAddOp1(v, OP_Yield, regAddrA);
|
| + sqlite3VdbeAddOp2(v, OP_If, regEofA, addrEofA);
|
| + sqlite3VdbeAddOp2(v, OP_Goto, 0, labelCmpr);
|
| +
|
| + /* Generate code to handle the case of A==B
|
| + */
|
| + if( op==TK_ALL ){
|
| + addrAeqB = addrAltB;
|
| + }else if( op==TK_INTERSECT ){
|
| + addrAeqB = addrAltB;
|
| + addrAltB++;
|
| + }else{
|
| + VdbeNoopComment((v, "A-eq-B subroutine"));
|
| + addrAeqB =
|
| + sqlite3VdbeAddOp1(v, OP_Yield, regAddrA);
|
| + sqlite3VdbeAddOp2(v, OP_If, regEofA, addrEofA);
|
| + sqlite3VdbeAddOp2(v, OP_Goto, 0, labelCmpr);
|
| + }
|
| +
|
| + /* Generate code to handle the case of A>B
|
| + */
|
| + VdbeNoopComment((v, "A-gt-B subroutine"));
|
| + addrAgtB = sqlite3VdbeCurrentAddr(v);
|
| + if( op==TK_ALL || op==TK_UNION ){
|
| + sqlite3VdbeAddOp2(v, OP_Gosub, regOutB, addrOutB);
|
| + }
|
| + sqlite3VdbeAddOp1(v, OP_Yield, regAddrB);
|
| + sqlite3VdbeAddOp2(v, OP_If, regEofB, addrEofB);
|
| + sqlite3VdbeAddOp2(v, OP_Goto, 0, labelCmpr);
|
| +
|
| + /* This code runs once to initialize everything.
|
| + */
|
| + sqlite3VdbeJumpHere(v, j1);
|
| + sqlite3VdbeAddOp2(v, OP_Integer, 0, regEofA);
|
| + sqlite3VdbeAddOp2(v, OP_Integer, 0, regEofB);
|
| + sqlite3VdbeAddOp2(v, OP_Gosub, regAddrA, addrSelectA);
|
| + sqlite3VdbeAddOp2(v, OP_Gosub, regAddrB, addrSelectB);
|
| + sqlite3VdbeAddOp2(v, OP_If, regEofA, addrEofA);
|
| + sqlite3VdbeAddOp2(v, OP_If, regEofB, addrEofB);
|
| +
|
| + /* Implement the main merge loop
|
| + */
|
| + sqlite3VdbeResolveLabel(v, labelCmpr);
|
| + sqlite3VdbeAddOp4(v, OP_Permutation, 0, 0, 0, (char*)aPermute, P4_INTARRAY);
|
| + sqlite3VdbeAddOp4(v, OP_Compare, destA.iMem, destB.iMem, nOrderBy,
|
| + (char*)pKeyMerge, P4_KEYINFO_HANDOFF);
|
| + sqlite3VdbeAddOp3(v, OP_Jump, addrAltB, addrAeqB, addrAgtB);
|
| +
|
| + /* Release temporary registers
|
| + */
|
| + if( regPrev ){
|
| + sqlite3ReleaseTempRange(pParse, regPrev, nOrderBy+1);
|
| + }
|
| +
|
| + /* Jump to the this point in order to terminate the query.
|
| + */
|
| + sqlite3VdbeResolveLabel(v, labelEnd);
|
| +
|
| + /* Set the number of output columns
|
| + */
|
| + if( pDest->eDest==SRT_Output ){
|
| + Select *pFirst = pPrior;
|
| + while( pFirst->pPrior ) pFirst = pFirst->pPrior;
|
| + generateColumnNames(pParse, 0, pFirst->pEList);
|
| + }
|
| +
|
| + /* Reassembly the compound query so that it will be freed correctly
|
| + ** by the calling function */
|
| + if( p->pPrior ){
|
| + sqlite3SelectDelete(db, p->pPrior);
|
| + }
|
| + p->pPrior = pPrior;
|
| +
|
| + /*** TBD: Insert subroutine calls to close cursors on incomplete
|
| + **** subqueries ****/
|
| + explainComposite(pParse, p->op, iSub1, iSub2, 0);
|
| + return SQLITE_OK;
|
| +}
|
| +#endif
|
| +
|
| +#if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
|
| +/* Forward Declarations */
|
| +static void substExprList(sqlite3*, ExprList*, int, ExprList*);
|
| +static void substSelect(sqlite3*, Select *, int, ExprList *);
|
| +
|
| +/*
|
| +** Scan through the expression pExpr. Replace every reference to
|
| +** a column in table number iTable with a copy of the iColumn-th
|
| +** entry in pEList. (But leave references to the ROWID column
|
| +** unchanged.)
|
| +**
|
| +** This routine is part of the flattening procedure. A subquery
|
| +** whose result set is defined by pEList appears as entry in the
|
| +** FROM clause of a SELECT such that the VDBE cursor assigned to that
|
| +** FORM clause entry is iTable. This routine make the necessary
|
| +** changes to pExpr so that it refers directly to the source table
|
| +** of the subquery rather the result set of the subquery.
|
| +*/
|
| +static Expr *substExpr(
|
| + sqlite3 *db, /* Report malloc errors to this connection */
|
| + Expr *pExpr, /* Expr in which substitution occurs */
|
| + int iTable, /* Table to be substituted */
|
| + ExprList *pEList /* Substitute expressions */
|
| +){
|
| + if( pExpr==0 ) return 0;
|
| + if( pExpr->op==TK_COLUMN && pExpr->iTable==iTable ){
|
| + if( pExpr->iColumn<0 ){
|
| + pExpr->op = TK_NULL;
|
| + }else{
|
| + Expr *pNew;
|
| + assert( pEList!=0 && pExpr->iColumn<pEList->nExpr );
|
| + assert( pExpr->pLeft==0 && pExpr->pRight==0 );
|
| + pNew = sqlite3ExprDup(db, pEList->a[pExpr->iColumn].pExpr, 0);
|
| + if( pNew && pExpr->pColl ){
|
| + pNew->pColl = pExpr->pColl;
|
| + }
|
| + sqlite3ExprDelete(db, pExpr);
|
| + pExpr = pNew;
|
| + }
|
| + }else{
|
| + pExpr->pLeft = substExpr(db, pExpr->pLeft, iTable, pEList);
|
| + pExpr->pRight = substExpr(db, pExpr->pRight, iTable, pEList);
|
| + if( ExprHasProperty(pExpr, EP_xIsSelect) ){
|
| + substSelect(db, pExpr->x.pSelect, iTable, pEList);
|
| + }else{
|
| + substExprList(db, pExpr->x.pList, iTable, pEList);
|
| + }
|
| + }
|
| + return pExpr;
|
| +}
|
| +static void substExprList(
|
| + sqlite3 *db, /* Report malloc errors here */
|
| + ExprList *pList, /* List to scan and in which to make substitutes */
|
| + int iTable, /* Table to be substituted */
|
| + ExprList *pEList /* Substitute values */
|
| +){
|
| + int i;
|
| + if( pList==0 ) return;
|
| + for(i=0; i<pList->nExpr; i++){
|
| + pList->a[i].pExpr = substExpr(db, pList->a[i].pExpr, iTable, pEList);
|
| + }
|
| +}
|
| +static void substSelect(
|
| + sqlite3 *db, /* Report malloc errors here */
|
| + Select *p, /* SELECT statement in which to make substitutions */
|
| + int iTable, /* Table to be replaced */
|
| + ExprList *pEList /* Substitute values */
|
| +){
|
| + SrcList *pSrc;
|
| + struct SrcList_item *pItem;
|
| + int i;
|
| + if( !p ) return;
|
| + substExprList(db, p->pEList, iTable, pEList);
|
| + substExprList(db, p->pGroupBy, iTable, pEList);
|
| + substExprList(db, p->pOrderBy, iTable, pEList);
|
| + p->pHaving = substExpr(db, p->pHaving, iTable, pEList);
|
| + p->pWhere = substExpr(db, p->pWhere, iTable, pEList);
|
| + substSelect(db, p->pPrior, iTable, pEList);
|
| + pSrc = p->pSrc;
|
| + assert( pSrc ); /* Even for (SELECT 1) we have: pSrc!=0 but pSrc->nSrc==0 */
|
| + if( ALWAYS(pSrc) ){
|
| + for(i=pSrc->nSrc, pItem=pSrc->a; i>0; i--, pItem++){
|
| + substSelect(db, pItem->pSelect, iTable, pEList);
|
| + }
|
| + }
|
| +}
|
| +#endif /* !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) */
|
| +
|
| +#if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
|
| +/*
|
| +** This routine attempts to flatten subqueries in order to speed
|
| +** execution. It returns 1 if it makes changes and 0 if no flattening
|
| +** occurs.
|
| +**
|
| +** To understand the concept of flattening, consider the following
|
| +** query:
|
| +**
|
| +** SELECT a FROM (SELECT x+y AS a FROM t1 WHERE z<100) WHERE a>5
|
| +**
|
| +** The default way of implementing this query is to execute the
|
| +** subquery first and store the results in a temporary table, then
|
| +** run the outer query on that temporary table. This requires two
|
| +** passes over the data. Furthermore, because the temporary table
|
| +** has no indices, the WHERE clause on the outer query cannot be
|
| +** optimized.
|
| +**
|
| +** This routine attempts to rewrite queries such as the above into
|
| +** a single flat select, like this:
|
| +**
|
| +** SELECT x+y AS a FROM t1 WHERE z<100 AND a>5
|
| +**
|
| +** The code generated for this simpification gives the same result
|
| +** but only has to scan the data once. And because indices might
|
| +** exist on the table t1, a complete scan of the data might be
|
| +** avoided.
|
| +**
|
| +** Flattening is only attempted if all of the following are true:
|
| +**
|
| +** (1) The subquery and the outer query do not both use aggregates.
|
| +**
|
| +** (2) The subquery is not an aggregate or the outer query is not a join.
|
| +**
|
| +** (3) The subquery is not the right operand of a left outer join
|
| +** (Originally ticket #306. Strengthened by ticket #3300)
|
| +**
|
| +** (4) The subquery is not DISTINCT.
|
| +**
|
| +** (**) At one point restrictions (4) and (5) defined a subset of DISTINCT
|
| +** sub-queries that were excluded from this optimization. Restriction
|
| +** (4) has since been expanded to exclude all DISTINCT subqueries.
|
| +**
|
| +** (6) The subquery does not use aggregates or the outer query is not
|
| +** DISTINCT.
|
| +**
|
| +** (7) The subquery has a FROM clause.
|
| +**
|
| +** (8) The subquery does not use LIMIT or the outer query is not a join.
|
| +**
|
| +** (9) The subquery does not use LIMIT or the outer query does not use
|
| +** aggregates.
|
| +**
|
| +** (10) The subquery does not use aggregates or the outer query does not
|
| +** use LIMIT.
|
| +**
|
| +** (11) The subquery and the outer query do not both have ORDER BY clauses.
|
| +**
|
| +** (**) Not implemented. Subsumed into restriction (3). Was previously
|
| +** a separate restriction deriving from ticket #350.
|
| +**
|
| +** (13) The subquery and outer query do not both use LIMIT.
|
| +**
|
| +** (14) The subquery does not use OFFSET.
|
| +**
|
| +** (15) The outer query is not part of a compound select or the
|
| +** subquery does not have a LIMIT clause.
|
| +** (See ticket #2339 and ticket [02a8e81d44]).
|
| +**
|
| +** (16) The outer query is not an aggregate or the subquery does
|
| +** not contain ORDER BY. (Ticket #2942) This used to not matter
|
| +** until we introduced the group_concat() function.
|
| +**
|
| +** (17) The sub-query is not a compound select, or it is a UNION ALL
|
| +** compound clause made up entirely of non-aggregate queries, and
|
| +** the parent query:
|
| +**
|
| +** * is not itself part of a compound select,
|
| +** * is not an aggregate or DISTINCT query, and
|
| +** * has no other tables or sub-selects in the FROM clause.
|
| +**
|
| +** The parent and sub-query may contain WHERE clauses. Subject to
|
| +** rules (11), (13) and (14), they may also contain ORDER BY,
|
| +** LIMIT and OFFSET clauses.
|
| +**
|
| +** (18) If the sub-query is a compound select, then all terms of the
|
| +** ORDER by clause of the parent must be simple references to
|
| +** columns of the sub-query.
|
| +**
|
| +** (19) The subquery does not use LIMIT or the outer query does not
|
| +** have a WHERE clause.
|
| +**
|
| +** (20) If the sub-query is a compound select, then it must not use
|
| +** an ORDER BY clause. Ticket #3773. We could relax this constraint
|
| +** somewhat by saying that the terms of the ORDER BY clause must
|
| +** appear as unmodified result columns in the outer query. But
|
| +** have other optimizations in mind to deal with that case.
|
| +**
|
| +** (21) The subquery does not use LIMIT or the outer query is not
|
| +** DISTINCT. (See ticket [752e1646fc]).
|
| +**
|
| +** In this routine, the "p" parameter is a pointer to the outer query.
|
| +** The subquery is p->pSrc->a[iFrom]. isAgg is true if the outer query
|
| +** uses aggregates and subqueryIsAgg is true if the subquery uses aggregates.
|
| +**
|
| +** If flattening is not attempted, this routine is a no-op and returns 0.
|
| +** If flattening is attempted this routine returns 1.
|
| +**
|
| +** All of the expression analysis must occur on both the outer query and
|
| +** the subquery before this routine runs.
|
| +*/
|
| +static int flattenSubquery(
|
| + Parse *pParse, /* Parsing context */
|
| + Select *p, /* The parent or outer SELECT statement */
|
| + int iFrom, /* Index in p->pSrc->a[] of the inner subquery */
|
| + int isAgg, /* True if outer SELECT uses aggregate functions */
|
| + int subqueryIsAgg /* True if the subquery uses aggregate functions */
|
| +){
|
| + const char *zSavedAuthContext = pParse->zAuthContext;
|
| + Select *pParent;
|
| + Select *pSub; /* The inner query or "subquery" */
|
| + Select *pSub1; /* Pointer to the rightmost select in sub-query */
|
| + SrcList *pSrc; /* The FROM clause of the outer query */
|
| + SrcList *pSubSrc; /* The FROM clause of the subquery */
|
| + ExprList *pList; /* The result set of the outer query */
|
| + int iParent; /* VDBE cursor number of the pSub result set temp table */
|
| + int i; /* Loop counter */
|
| + Expr *pWhere; /* The WHERE clause */
|
| + struct SrcList_item *pSubitem; /* The subquery */
|
| + sqlite3 *db = pParse->db;
|
| +
|
| + /* Check to see if flattening is permitted. Return 0 if not.
|
| + */
|
| + assert( p!=0 );
|
| + assert( p->pPrior==0 ); /* Unable to flatten compound queries */
|
| + if( db->flags & SQLITE_QueryFlattener ) return 0;
|
| + pSrc = p->pSrc;
|
| + assert( pSrc && iFrom>=0 && iFrom<pSrc->nSrc );
|
| + pSubitem = &pSrc->a[iFrom];
|
| + iParent = pSubitem->iCursor;
|
| + pSub = pSubitem->pSelect;
|
| + assert( pSub!=0 );
|
| + if( isAgg && subqueryIsAgg ) return 0; /* Restriction (1) */
|
| + if( subqueryIsAgg && pSrc->nSrc>1 ) return 0; /* Restriction (2) */
|
| + pSubSrc = pSub->pSrc;
|
| + assert( pSubSrc );
|
| + /* Prior to version 3.1.2, when LIMIT and OFFSET had to be simple constants,
|
| + ** not arbitrary expresssions, we allowed some combining of LIMIT and OFFSET
|
| + ** because they could be computed at compile-time. But when LIMIT and OFFSET
|
| + ** became arbitrary expressions, we were forced to add restrictions (13)
|
| + ** and (14). */
|
| + if( pSub->pLimit && p->pLimit ) return 0; /* Restriction (13) */
|
| + if( pSub->pOffset ) return 0; /* Restriction (14) */
|
| + if( p->pRightmost && pSub->pLimit ){
|
| + return 0; /* Restriction (15) */
|
| + }
|
| + if( pSubSrc->nSrc==0 ) return 0; /* Restriction (7) */
|
| + if( pSub->selFlags & SF_Distinct ) return 0; /* Restriction (5) */
|
| + if( pSub->pLimit && (pSrc->nSrc>1 || isAgg) ){
|
| + return 0; /* Restrictions (8)(9) */
|
| + }
|
| + if( (p->selFlags & SF_Distinct)!=0 && subqueryIsAgg ){
|
| + return 0; /* Restriction (6) */
|
| + }
|
| + if( p->pOrderBy && pSub->pOrderBy ){
|
| + return 0; /* Restriction (11) */
|
| + }
|
| + if( isAgg && pSub->pOrderBy ) return 0; /* Restriction (16) */
|
| + if( pSub->pLimit && p->pWhere ) return 0; /* Restriction (19) */
|
| + if( pSub->pLimit && (p->selFlags & SF_Distinct)!=0 ){
|
| + return 0; /* Restriction (21) */
|
| + }
|
| +
|
| + /* OBSOLETE COMMENT 1:
|
| + ** Restriction 3: If the subquery is a join, make sure the subquery is
|
| + ** not used as the right operand of an outer join. Examples of why this
|
| + ** is not allowed:
|
| + **
|
| + ** t1 LEFT OUTER JOIN (t2 JOIN t3)
|
| + **
|
| + ** If we flatten the above, we would get
|
| + **
|
| + ** (t1 LEFT OUTER JOIN t2) JOIN t3
|
| + **
|
| + ** which is not at all the same thing.
|
| + **
|
| + ** OBSOLETE COMMENT 2:
|
| + ** Restriction 12: If the subquery is the right operand of a left outer
|
| + ** join, make sure the subquery has no WHERE clause.
|
| + ** An examples of why this is not allowed:
|
| + **
|
| + ** t1 LEFT OUTER JOIN (SELECT * FROM t2 WHERE t2.x>0)
|
| + **
|
| + ** If we flatten the above, we would get
|
| + **
|
| + ** (t1 LEFT OUTER JOIN t2) WHERE t2.x>0
|
| + **
|
| + ** But the t2.x>0 test will always fail on a NULL row of t2, which
|
| + ** effectively converts the OUTER JOIN into an INNER JOIN.
|
| + **
|
| + ** THIS OVERRIDES OBSOLETE COMMENTS 1 AND 2 ABOVE:
|
| + ** Ticket #3300 shows that flattening the right term of a LEFT JOIN
|
| + ** is fraught with danger. Best to avoid the whole thing. If the
|
| + ** subquery is the right term of a LEFT JOIN, then do not flatten.
|
| + */
|
| + if( (pSubitem->jointype & JT_OUTER)!=0 ){
|
| + return 0;
|
| + }
|
| +
|
| + /* Restriction 17: If the sub-query is a compound SELECT, then it must
|
| + ** use only the UNION ALL operator. And none of the simple select queries
|
| + ** that make up the compound SELECT are allowed to be aggregate or distinct
|
| + ** queries.
|
| + */
|
| + if( pSub->pPrior ){
|
| + if( pSub->pOrderBy ){
|
| + return 0; /* Restriction 20 */
|
| + }
|
| + if( isAgg || (p->selFlags & SF_Distinct)!=0 || pSrc->nSrc!=1 ){
|
| + return 0;
|
| + }
|
| + for(pSub1=pSub; pSub1; pSub1=pSub1->pPrior){
|
| + testcase( (pSub1->selFlags & (SF_Distinct|SF_Aggregate))==SF_Distinct );
|
| + testcase( (pSub1->selFlags & (SF_Distinct|SF_Aggregate))==SF_Aggregate );
|
| + if( (pSub1->selFlags & (SF_Distinct|SF_Aggregate))!=0
|
| + || (pSub1->pPrior && pSub1->op!=TK_ALL)
|
| + || NEVER(pSub1->pSrc==0) || pSub1->pSrc->nSrc!=1
|
| + ){
|
| + return 0;
|
| + }
|
| + }
|
| +
|
| + /* Restriction 18. */
|
| + if( p->pOrderBy ){
|
| + int ii;
|
| + for(ii=0; ii<p->pOrderBy->nExpr; ii++){
|
| + if( p->pOrderBy->a[ii].iCol==0 ) return 0;
|
| + }
|
| + }
|
| + }
|
| +
|
| + /***** If we reach this point, flattening is permitted. *****/
|
| +
|
| + /* Authorize the subquery */
|
| + pParse->zAuthContext = pSubitem->zName;
|
| + sqlite3AuthCheck(pParse, SQLITE_SELECT, 0, 0, 0);
|
| + pParse->zAuthContext = zSavedAuthContext;
|
| +
|
| + /* If the sub-query is a compound SELECT statement, then (by restrictions
|
| + ** 17 and 18 above) it must be a UNION ALL and the parent query must
|
| + ** be of the form:
|
| + **
|
| + ** SELECT <expr-list> FROM (<sub-query>) <where-clause>
|
| + **
|
| + ** followed by any ORDER BY, LIMIT and/or OFFSET clauses. This block
|
| + ** creates N-1 copies of the parent query without any ORDER BY, LIMIT or
|
| + ** OFFSET clauses and joins them to the left-hand-side of the original
|
| + ** using UNION ALL operators. In this case N is the number of simple
|
| + ** select statements in the compound sub-query.
|
| + **
|
| + ** Example:
|
| + **
|
| + ** SELECT a+1 FROM (
|
| + ** SELECT x FROM tab
|
| + ** UNION ALL
|
| + ** SELECT y FROM tab
|
| + ** UNION ALL
|
| + ** SELECT abs(z*2) FROM tab2
|
| + ** ) WHERE a!=5 ORDER BY 1
|
| + **
|
| + ** Transformed into:
|
| + **
|
| + ** SELECT x+1 FROM tab WHERE x+1!=5
|
| + ** UNION ALL
|
| + ** SELECT y+1 FROM tab WHERE y+1!=5
|
| + ** UNION ALL
|
| + ** SELECT abs(z*2)+1 FROM tab2 WHERE abs(z*2)+1!=5
|
| + ** ORDER BY 1
|
| + **
|
| + ** We call this the "compound-subquery flattening".
|
| + */
|
| + for(pSub=pSub->pPrior; pSub; pSub=pSub->pPrior){
|
| + Select *pNew;
|
| + ExprList *pOrderBy = p->pOrderBy;
|
| + Expr *pLimit = p->pLimit;
|
| + Select *pPrior = p->pPrior;
|
| + p->pOrderBy = 0;
|
| + p->pSrc = 0;
|
| + p->pPrior = 0;
|
| + p->pLimit = 0;
|
| + pNew = sqlite3SelectDup(db, p, 0);
|
| + p->pLimit = pLimit;
|
| + p->pOrderBy = pOrderBy;
|
| + p->pSrc = pSrc;
|
| + p->op = TK_ALL;
|
| + p->pRightmost = 0;
|
| + if( pNew==0 ){
|
| + pNew = pPrior;
|
| + }else{
|
| + pNew->pPrior = pPrior;
|
| + pNew->pRightmost = 0;
|
| + }
|
| + p->pPrior = pNew;
|
| + if( db->mallocFailed ) return 1;
|
| + }
|
| +
|
| + /* Begin flattening the iFrom-th entry of the FROM clause
|
| + ** in the outer query.
|
| + */
|
| + pSub = pSub1 = pSubitem->pSelect;
|
| +
|
| + /* Delete the transient table structure associated with the
|
| + ** subquery
|
| + */
|
| + sqlite3DbFree(db, pSubitem->zDatabase);
|
| + sqlite3DbFree(db, pSubitem->zName);
|
| + sqlite3DbFree(db, pSubitem->zAlias);
|
| + pSubitem->zDatabase = 0;
|
| + pSubitem->zName = 0;
|
| + pSubitem->zAlias = 0;
|
| + pSubitem->pSelect = 0;
|
| +
|
| + /* Defer deleting the Table object associated with the
|
| + ** subquery until code generation is
|
| + ** complete, since there may still exist Expr.pTab entries that
|
| + ** refer to the subquery even after flattening. Ticket #3346.
|
| + **
|
| + ** pSubitem->pTab is always non-NULL by test restrictions and tests above.
|
| + */
|
| + if( ALWAYS(pSubitem->pTab!=0) ){
|
| + Table *pTabToDel = pSubitem->pTab;
|
| + if( pTabToDel->nRef==1 ){
|
| + Parse *pToplevel = sqlite3ParseToplevel(pParse);
|
| + pTabToDel->pNextZombie = pToplevel->pZombieTab;
|
| + pToplevel->pZombieTab = pTabToDel;
|
| + }else{
|
| + pTabToDel->nRef--;
|
| + }
|
| + pSubitem->pTab = 0;
|
| + }
|
| +
|
| + /* The following loop runs once for each term in a compound-subquery
|
| + ** flattening (as described above). If we are doing a different kind
|
| + ** of flattening - a flattening other than a compound-subquery flattening -
|
| + ** then this loop only runs once.
|
| + **
|
| + ** This loop moves all of the FROM elements of the subquery into the
|
| + ** the FROM clause of the outer query. Before doing this, remember
|
| + ** the cursor number for the original outer query FROM element in
|
| + ** iParent. The iParent cursor will never be used. Subsequent code
|
| + ** will scan expressions looking for iParent references and replace
|
| + ** those references with expressions that resolve to the subquery FROM
|
| + ** elements we are now copying in.
|
| + */
|
| + for(pParent=p; pParent; pParent=pParent->pPrior, pSub=pSub->pPrior){
|
| + int nSubSrc;
|
| + u8 jointype = 0;
|
| + pSubSrc = pSub->pSrc; /* FROM clause of subquery */
|
| + nSubSrc = pSubSrc->nSrc; /* Number of terms in subquery FROM clause */
|
| + pSrc = pParent->pSrc; /* FROM clause of the outer query */
|
| +
|
| + if( pSrc ){
|
| + assert( pParent==p ); /* First time through the loop */
|
| + jointype = pSubitem->jointype;
|
| + }else{
|
| + assert( pParent!=p ); /* 2nd and subsequent times through the loop */
|
| + pSrc = pParent->pSrc = sqlite3SrcListAppend(db, 0, 0, 0);
|
| + if( pSrc==0 ){
|
| + assert( db->mallocFailed );
|
| + break;
|
| + }
|
| + }
|
| +
|
| + /* The subquery uses a single slot of the FROM clause of the outer
|
| + ** query. If the subquery has more than one element in its FROM clause,
|
| + ** then expand the outer query to make space for it to hold all elements
|
| + ** of the subquery.
|
| + **
|
| + ** Example:
|
| + **
|
| + ** SELECT * FROM tabA, (SELECT * FROM sub1, sub2), tabB;
|
| + **
|
| + ** The outer query has 3 slots in its FROM clause. One slot of the
|
| + ** outer query (the middle slot) is used by the subquery. The next
|
| + ** block of code will expand the out query to 4 slots. The middle
|
| + ** slot is expanded to two slots in order to make space for the
|
| + ** two elements in the FROM clause of the subquery.
|
| + */
|
| + if( nSubSrc>1 ){
|
| + pParent->pSrc = pSrc = sqlite3SrcListEnlarge(db, pSrc, nSubSrc-1,iFrom+1);
|
| + if( db->mallocFailed ){
|
| + break;
|
| + }
|
| + }
|
| +
|
| + /* Transfer the FROM clause terms from the subquery into the
|
| + ** outer query.
|
| + */
|
| + for(i=0; i<nSubSrc; i++){
|
| + sqlite3IdListDelete(db, pSrc->a[i+iFrom].pUsing);
|
| + pSrc->a[i+iFrom] = pSubSrc->a[i];
|
| + memset(&pSubSrc->a[i], 0, sizeof(pSubSrc->a[i]));
|
| + }
|
| + pSrc->a[iFrom].jointype = jointype;
|
| +
|
| + /* Now begin substituting subquery result set expressions for
|
| + ** references to the iParent in the outer query.
|
| + **
|
| + ** Example:
|
| + **
|
| + ** SELECT a+5, b*10 FROM (SELECT x*3 AS a, y+10 AS b FROM t1) WHERE a>b;
|
| + ** \ \_____________ subquery __________/ /
|
| + ** \_____________________ outer query ______________________________/
|
| + **
|
| + ** We look at every expression in the outer query and every place we see
|
| + ** "a" we substitute "x*3" and every place we see "b" we substitute "y+10".
|
| + */
|
| + pList = pParent->pEList;
|
| + for(i=0; i<pList->nExpr; i++){
|
| + if( pList->a[i].zName==0 ){
|
| + const char *zSpan = pList->a[i].zSpan;
|
| + if( ALWAYS(zSpan) ){
|
| + pList->a[i].zName = sqlite3DbStrDup(db, zSpan);
|
| + }
|
| + }
|
| + }
|
| + substExprList(db, pParent->pEList, iParent, pSub->pEList);
|
| + if( isAgg ){
|
| + substExprList(db, pParent->pGroupBy, iParent, pSub->pEList);
|
| + pParent->pHaving = substExpr(db, pParent->pHaving, iParent, pSub->pEList);
|
| + }
|
| + if( pSub->pOrderBy ){
|
| + assert( pParent->pOrderBy==0 );
|
| + pParent->pOrderBy = pSub->pOrderBy;
|
| + pSub->pOrderBy = 0;
|
| + }else if( pParent->pOrderBy ){
|
| + substExprList(db, pParent->pOrderBy, iParent, pSub->pEList);
|
| + }
|
| + if( pSub->pWhere ){
|
| + pWhere = sqlite3ExprDup(db, pSub->pWhere, 0);
|
| + }else{
|
| + pWhere = 0;
|
| + }
|
| + if( subqueryIsAgg ){
|
| + assert( pParent->pHaving==0 );
|
| + pParent->pHaving = pParent->pWhere;
|
| + pParent->pWhere = pWhere;
|
| + pParent->pHaving = substExpr(db, pParent->pHaving, iParent, pSub->pEList);
|
| + pParent->pHaving = sqlite3ExprAnd(db, pParent->pHaving,
|
| + sqlite3ExprDup(db, pSub->pHaving, 0));
|
| + assert( pParent->pGroupBy==0 );
|
| + pParent->pGroupBy = sqlite3ExprListDup(db, pSub->pGroupBy, 0);
|
| + }else{
|
| + pParent->pWhere = substExpr(db, pParent->pWhere, iParent, pSub->pEList);
|
| + pParent->pWhere = sqlite3ExprAnd(db, pParent->pWhere, pWhere);
|
| + }
|
| +
|
| + /* The flattened query is distinct if either the inner or the
|
| + ** outer query is distinct.
|
| + */
|
| + pParent->selFlags |= pSub->selFlags & SF_Distinct;
|
| +
|
| + /*
|
| + ** SELECT ... FROM (SELECT ... LIMIT a OFFSET b) LIMIT x OFFSET y;
|
| + **
|
| + ** One is tempted to try to add a and b to combine the limits. But this
|
| + ** does not work if either limit is negative.
|
| + */
|
| + if( pSub->pLimit ){
|
| + pParent->pLimit = pSub->pLimit;
|
| + pSub->pLimit = 0;
|
| + }
|
| + }
|
| +
|
| + /* Finially, delete what is left of the subquery and return
|
| + ** success.
|
| + */
|
| + sqlite3SelectDelete(db, pSub1);
|
| +
|
| + return 1;
|
| +}
|
| +#endif /* !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) */
|
| +
|
| +/*
|
| +** Analyze the SELECT statement passed as an argument to see if it
|
| +** is a min() or max() query. Return WHERE_ORDERBY_MIN or WHERE_ORDERBY_MAX if
|
| +** it is, or 0 otherwise. At present, a query is considered to be
|
| +** a min()/max() query if:
|
| +**
|
| +** 1. There is a single object in the FROM clause.
|
| +**
|
| +** 2. There is a single expression in the result set, and it is
|
| +** either min(x) or max(x), where x is a column reference.
|
| +*/
|
| +static u8 minMaxQuery(Select *p){
|
| + Expr *pExpr;
|
| + ExprList *pEList = p->pEList;
|
| +
|
| + if( pEList->nExpr!=1 ) return WHERE_ORDERBY_NORMAL;
|
| + pExpr = pEList->a[0].pExpr;
|
| + if( pExpr->op!=TK_AGG_FUNCTION ) return 0;
|
| + if( NEVER(ExprHasProperty(pExpr, EP_xIsSelect)) ) return 0;
|
| + pEList = pExpr->x.pList;
|
| + if( pEList==0 || pEList->nExpr!=1 ) return 0;
|
| + if( pEList->a[0].pExpr->op!=TK_AGG_COLUMN ) return WHERE_ORDERBY_NORMAL;
|
| + assert( !ExprHasProperty(pExpr, EP_IntValue) );
|
| + if( sqlite3StrICmp(pExpr->u.zToken,"min")==0 ){
|
| + return WHERE_ORDERBY_MIN;
|
| + }else if( sqlite3StrICmp(pExpr->u.zToken,"max")==0 ){
|
| + return WHERE_ORDERBY_MAX;
|
| + }
|
| + return WHERE_ORDERBY_NORMAL;
|
| +}
|
| +
|
| +/*
|
| +** The select statement passed as the first argument is an aggregate query.
|
| +** The second argment is the associated aggregate-info object. This
|
| +** function tests if the SELECT is of the form:
|
| +**
|
| +** SELECT count(*) FROM <tbl>
|
| +**
|
| +** where table is a database table, not a sub-select or view. If the query
|
| +** does match this pattern, then a pointer to the Table object representing
|
| +** <tbl> is returned. Otherwise, 0 is returned.
|
| +*/
|
| +static Table *isSimpleCount(Select *p, AggInfo *pAggInfo){
|
| + Table *pTab;
|
| + Expr *pExpr;
|
| +
|
| + assert( !p->pGroupBy );
|
| +
|
| + if( p->pWhere || p->pEList->nExpr!=1
|
| + || p->pSrc->nSrc!=1 || p->pSrc->a[0].pSelect
|
| + ){
|
| + return 0;
|
| + }
|
| + pTab = p->pSrc->a[0].pTab;
|
| + pExpr = p->pEList->a[0].pExpr;
|
| + assert( pTab && !pTab->pSelect && pExpr );
|
| +
|
| + if( IsVirtual(pTab) ) return 0;
|
| + if( pExpr->op!=TK_AGG_FUNCTION ) return 0;
|
| + if( (pAggInfo->aFunc[0].pFunc->flags&SQLITE_FUNC_COUNT)==0 ) return 0;
|
| + if( pExpr->flags&EP_Distinct ) return 0;
|
| +
|
| + return pTab;
|
| +}
|
| +
|
| +/*
|
| +** If the source-list item passed as an argument was augmented with an
|
| +** INDEXED BY clause, then try to locate the specified index. If there
|
| +** was such a clause and the named index cannot be found, return
|
| +** SQLITE_ERROR and leave an error in pParse. Otherwise, populate
|
| +** pFrom->pIndex and return SQLITE_OK.
|
| +*/
|
| +int sqlite3IndexedByLookup(Parse *pParse, struct SrcList_item *pFrom){
|
| + if( pFrom->pTab && pFrom->zIndex ){
|
| + Table *pTab = pFrom->pTab;
|
| + char *zIndex = pFrom->zIndex;
|
| + Index *pIdx;
|
| + for(pIdx=pTab->pIndex;
|
| + pIdx && sqlite3StrICmp(pIdx->zName, zIndex);
|
| + pIdx=pIdx->pNext
|
| + );
|
| + if( !pIdx ){
|
| + sqlite3ErrorMsg(pParse, "no such index: %s", zIndex, 0);
|
| + pParse->checkSchema = 1;
|
| + return SQLITE_ERROR;
|
| + }
|
| + pFrom->pIndex = pIdx;
|
| + }
|
| + return SQLITE_OK;
|
| +}
|
| +
|
| +/*
|
| +** This routine is a Walker callback for "expanding" a SELECT statement.
|
| +** "Expanding" means to do the following:
|
| +**
|
| +** (1) Make sure VDBE cursor numbers have been assigned to every
|
| +** element of the FROM clause.
|
| +**
|
| +** (2) Fill in the pTabList->a[].pTab fields in the SrcList that
|
| +** defines FROM clause. When views appear in the FROM clause,
|
| +** fill pTabList->a[].pSelect with a copy of the SELECT statement
|
| +** that implements the view. A copy is made of the view's SELECT
|
| +** statement so that we can freely modify or delete that statement
|
| +** without worrying about messing up the presistent representation
|
| +** of the view.
|
| +**
|
| +** (3) Add terms to the WHERE clause to accomodate the NATURAL keyword
|
| +** on joins and the ON and USING clause of joins.
|
| +**
|
| +** (4) Scan the list of columns in the result set (pEList) looking
|
| +** for instances of the "*" operator or the TABLE.* operator.
|
| +** If found, expand each "*" to be every column in every table
|
| +** and TABLE.* to be every column in TABLE.
|
| +**
|
| +*/
|
| +static int selectExpander(Walker *pWalker, Select *p){
|
| + Parse *pParse = pWalker->pParse;
|
| + int i, j, k;
|
| + SrcList *pTabList;
|
| + ExprList *pEList;
|
| + struct SrcList_item *pFrom;
|
| + sqlite3 *db = pParse->db;
|
| +
|
| + if( db->mallocFailed ){
|
| + return WRC_Abort;
|
| + }
|
| + if( NEVER(p->pSrc==0) || (p->selFlags & SF_Expanded)!=0 ){
|
| + return WRC_Prune;
|
| + }
|
| + p->selFlags |= SF_Expanded;
|
| + pTabList = p->pSrc;
|
| + pEList = p->pEList;
|
| +
|
| + /* Make sure cursor numbers have been assigned to all entries in
|
| + ** the FROM clause of the SELECT statement.
|
| + */
|
| + sqlite3SrcListAssignCursors(pParse, pTabList);
|
| +
|
| + /* Look up every table named in the FROM clause of the select. If
|
| + ** an entry of the FROM clause is a subquery instead of a table or view,
|
| + ** then create a transient table structure to describe the subquery.
|
| + */
|
| + for(i=0, pFrom=pTabList->a; i<pTabList->nSrc; i++, pFrom++){
|
| + Table *pTab;
|
| + if( pFrom->pTab!=0 ){
|
| + /* This statement has already been prepared. There is no need
|
| + ** to go further. */
|
| + assert( i==0 );
|
| + return WRC_Prune;
|
| + }
|
| + if( pFrom->zName==0 ){
|
| +#ifndef SQLITE_OMIT_SUBQUERY
|
| + Select *pSel = pFrom->pSelect;
|
| + /* A sub-query in the FROM clause of a SELECT */
|
| + assert( pSel!=0 );
|
| + assert( pFrom->pTab==0 );
|
| + sqlite3WalkSelect(pWalker, pSel);
|
| + pFrom->pTab = pTab = sqlite3DbMallocZero(db, sizeof(Table));
|
| + if( pTab==0 ) return WRC_Abort;
|
| + pTab->nRef = 1;
|
| + pTab->zName = sqlite3MPrintf(db, "sqlite_subquery_%p_", (void*)pTab);
|
| + while( pSel->pPrior ){ pSel = pSel->pPrior; }
|
| + selectColumnsFromExprList(pParse, pSel->pEList, &pTab->nCol, &pTab->aCol);
|
| + pTab->iPKey = -1;
|
| + pTab->nRowEst = 1000000;
|
| + pTab->tabFlags |= TF_Ephemeral;
|
| +#endif
|
| + }else{
|
| + /* An ordinary table or view name in the FROM clause */
|
| + assert( pFrom->pTab==0 );
|
| + pFrom->pTab = pTab =
|
| + sqlite3LocateTable(pParse,0,pFrom->zName,pFrom->zDatabase);
|
| + if( pTab==0 ) return WRC_Abort;
|
| + pTab->nRef++;
|
| +#if !defined(SQLITE_OMIT_VIEW) || !defined (SQLITE_OMIT_VIRTUALTABLE)
|
| + if( pTab->pSelect || IsVirtual(pTab) ){
|
| + /* We reach here if the named table is a really a view */
|
| + if( sqlite3ViewGetColumnNames(pParse, pTab) ) return WRC_Abort;
|
| + assert( pFrom->pSelect==0 );
|
| + pFrom->pSelect = sqlite3SelectDup(db, pTab->pSelect, 0);
|
| + sqlite3WalkSelect(pWalker, pFrom->pSelect);
|
| + }
|
| +#endif
|
| + }
|
| +
|
| + /* Locate the index named by the INDEXED BY clause, if any. */
|
| + if( sqlite3IndexedByLookup(pParse, pFrom) ){
|
| + return WRC_Abort;
|
| + }
|
| + }
|
| +
|
| + /* Process NATURAL keywords, and ON and USING clauses of joins.
|
| + */
|
| + if( db->mallocFailed || sqliteProcessJoin(pParse, p) ){
|
| + return WRC_Abort;
|
| + }
|
| +
|
| + /* For every "*" that occurs in the column list, insert the names of
|
| + ** all columns in all tables. And for every TABLE.* insert the names
|
| + ** of all columns in TABLE. The parser inserted a special expression
|
| + ** with the TK_ALL operator for each "*" that it found in the column list.
|
| + ** The following code just has to locate the TK_ALL expressions and expand
|
| + ** each one to the list of all columns in all tables.
|
| + **
|
| + ** The first loop just checks to see if there are any "*" operators
|
| + ** that need expanding.
|
| + */
|
| + for(k=0; k<pEList->nExpr; k++){
|
| + Expr *pE = pEList->a[k].pExpr;
|
| + if( pE->op==TK_ALL ) break;
|
| + assert( pE->op!=TK_DOT || pE->pRight!=0 );
|
| + assert( pE->op!=TK_DOT || (pE->pLeft!=0 && pE->pLeft->op==TK_ID) );
|
| + if( pE->op==TK_DOT && pE->pRight->op==TK_ALL ) break;
|
| + }
|
| + if( k<pEList->nExpr ){
|
| + /*
|
| + ** If we get here it means the result set contains one or more "*"
|
| + ** operators that need to be expanded. Loop through each expression
|
| + ** in the result set and expand them one by one.
|
| + */
|
| + struct ExprList_item *a = pEList->a;
|
| + ExprList *pNew = 0;
|
| + int flags = pParse->db->flags;
|
| + int longNames = (flags & SQLITE_FullColNames)!=0
|
| + && (flags & SQLITE_ShortColNames)==0;
|
| +
|
| + for(k=0; k<pEList->nExpr; k++){
|
| + Expr *pE = a[k].pExpr;
|
| + assert( pE->op!=TK_DOT || pE->pRight!=0 );
|
| + if( pE->op!=TK_ALL && (pE->op!=TK_DOT || pE->pRight->op!=TK_ALL) ){
|
| + /* This particular expression does not need to be expanded.
|
| + */
|
| + pNew = sqlite3ExprListAppend(pParse, pNew, a[k].pExpr);
|
| + if( pNew ){
|
| + pNew->a[pNew->nExpr-1].zName = a[k].zName;
|
| + pNew->a[pNew->nExpr-1].zSpan = a[k].zSpan;
|
| + a[k].zName = 0;
|
| + a[k].zSpan = 0;
|
| + }
|
| + a[k].pExpr = 0;
|
| + }else{
|
| + /* This expression is a "*" or a "TABLE.*" and needs to be
|
| + ** expanded. */
|
| + int tableSeen = 0; /* Set to 1 when TABLE matches */
|
| + char *zTName; /* text of name of TABLE */
|
| + if( pE->op==TK_DOT ){
|
| + assert( pE->pLeft!=0 );
|
| + assert( !ExprHasProperty(pE->pLeft, EP_IntValue) );
|
| + zTName = pE->pLeft->u.zToken;
|
| + }else{
|
| + zTName = 0;
|
| + }
|
| + for(i=0, pFrom=pTabList->a; i<pTabList->nSrc; i++, pFrom++){
|
| + Table *pTab = pFrom->pTab;
|
| + char *zTabName = pFrom->zAlias;
|
| + if( zTabName==0 ){
|
| + zTabName = pTab->zName;
|
| + }
|
| + if( db->mallocFailed ) break;
|
| + if( zTName && sqlite3StrICmp(zTName, zTabName)!=0 ){
|
| + continue;
|
| + }
|
| + tableSeen = 1;
|
| + for(j=0; j<pTab->nCol; j++){
|
| + Expr *pExpr, *pRight;
|
| + char *zName = pTab->aCol[j].zName;
|
| + char *zColname; /* The computed column name */
|
| + char *zToFree; /* Malloced string that needs to be freed */
|
| + Token sColname; /* Computed column name as a token */
|
| +
|
| + /* If a column is marked as 'hidden' (currently only possible
|
| + ** for virtual tables), do not include it in the expanded
|
| + ** result-set list.
|
| + */
|
| + if( IsHiddenColumn(&pTab->aCol[j]) ){
|
| + assert(IsVirtual(pTab));
|
| + continue;
|
| + }
|
| +
|
| + if( i>0 && zTName==0 ){
|
| + if( (pFrom->jointype & JT_NATURAL)!=0
|
| + && tableAndColumnIndex(pTabList, i, zName, 0, 0)
|
| + ){
|
| + /* In a NATURAL join, omit the join columns from the
|
| + ** table to the right of the join */
|
| + continue;
|
| + }
|
| + if( sqlite3IdListIndex(pFrom->pUsing, zName)>=0 ){
|
| + /* In a join with a USING clause, omit columns in the
|
| + ** using clause from the table on the right. */
|
| + continue;
|
| + }
|
| + }
|
| + pRight = sqlite3Expr(db, TK_ID, zName);
|
| + zColname = zName;
|
| + zToFree = 0;
|
| + if( longNames || pTabList->nSrc>1 ){
|
| + Expr *pLeft;
|
| + pLeft = sqlite3Expr(db, TK_ID, zTabName);
|
| + pExpr = sqlite3PExpr(pParse, TK_DOT, pLeft, pRight, 0);
|
| + if( longNames ){
|
| + zColname = sqlite3MPrintf(db, "%s.%s", zTabName, zName);
|
| + zToFree = zColname;
|
| + }
|
| + }else{
|
| + pExpr = pRight;
|
| + }
|
| + pNew = sqlite3ExprListAppend(pParse, pNew, pExpr);
|
| + sColname.z = zColname;
|
| + sColname.n = sqlite3Strlen30(zColname);
|
| + sqlite3ExprListSetName(pParse, pNew, &sColname, 0);
|
| + sqlite3DbFree(db, zToFree);
|
| + }
|
| + }
|
| + if( !tableSeen ){
|
| + if( zTName ){
|
| + sqlite3ErrorMsg(pParse, "no such table: %s", zTName);
|
| + }else{
|
| + sqlite3ErrorMsg(pParse, "no tables specified");
|
| + }
|
| + }
|
| + }
|
| + }
|
| + sqlite3ExprListDelete(db, pEList);
|
| + p->pEList = pNew;
|
| + }
|
| +#if SQLITE_MAX_COLUMN
|
| + if( p->pEList && p->pEList->nExpr>db->aLimit[SQLITE_LIMIT_COLUMN] ){
|
| + sqlite3ErrorMsg(pParse, "too many columns in result set");
|
| + }
|
| +#endif
|
| + return WRC_Continue;
|
| +}
|
| +
|
| +/*
|
| +** No-op routine for the parse-tree walker.
|
| +**
|
| +** When this routine is the Walker.xExprCallback then expression trees
|
| +** are walked without any actions being taken at each node. Presumably,
|
| +** when this routine is used for Walker.xExprCallback then
|
| +** Walker.xSelectCallback is set to do something useful for every
|
| +** subquery in the parser tree.
|
| +*/
|
| +static int exprWalkNoop(Walker *NotUsed, Expr *NotUsed2){
|
| + UNUSED_PARAMETER2(NotUsed, NotUsed2);
|
| + return WRC_Continue;
|
| +}
|
| +
|
| +/*
|
| +** This routine "expands" a SELECT statement and all of its subqueries.
|
| +** For additional information on what it means to "expand" a SELECT
|
| +** statement, see the comment on the selectExpand worker callback above.
|
| +**
|
| +** Expanding a SELECT statement is the first step in processing a
|
| +** SELECT statement. The SELECT statement must be expanded before
|
| +** name resolution is performed.
|
| +**
|
| +** If anything goes wrong, an error message is written into pParse.
|
| +** The calling function can detect the problem by looking at pParse->nErr
|
| +** and/or pParse->db->mallocFailed.
|
| +*/
|
| +static void sqlite3SelectExpand(Parse *pParse, Select *pSelect){
|
| + Walker w;
|
| + w.xSelectCallback = selectExpander;
|
| + w.xExprCallback = exprWalkNoop;
|
| + w.pParse = pParse;
|
| + sqlite3WalkSelect(&w, pSelect);
|
| +}
|
| +
|
| +
|
| +#ifndef SQLITE_OMIT_SUBQUERY
|
| +/*
|
| +** This is a Walker.xSelectCallback callback for the sqlite3SelectTypeInfo()
|
| +** interface.
|
| +**
|
| +** For each FROM-clause subquery, add Column.zType and Column.zColl
|
| +** information to the Table structure that represents the result set
|
| +** of that subquery.
|
| +**
|
| +** The Table structure that represents the result set was constructed
|
| +** by selectExpander() but the type and collation information was omitted
|
| +** at that point because identifiers had not yet been resolved. This
|
| +** routine is called after identifier resolution.
|
| +*/
|
| +static int selectAddSubqueryTypeInfo(Walker *pWalker, Select *p){
|
| + Parse *pParse;
|
| + int i;
|
| + SrcList *pTabList;
|
| + struct SrcList_item *pFrom;
|
| +
|
| + assert( p->selFlags & SF_Resolved );
|
| + if( (p->selFlags & SF_HasTypeInfo)==0 ){
|
| + p->selFlags |= SF_HasTypeInfo;
|
| + pParse = pWalker->pParse;
|
| + pTabList = p->pSrc;
|
| + for(i=0, pFrom=pTabList->a; i<pTabList->nSrc; i++, pFrom++){
|
| + Table *pTab = pFrom->pTab;
|
| + if( ALWAYS(pTab!=0) && (pTab->tabFlags & TF_Ephemeral)!=0 ){
|
| + /* A sub-query in the FROM clause of a SELECT */
|
| + Select *pSel = pFrom->pSelect;
|
| + assert( pSel );
|
| + while( pSel->pPrior ) pSel = pSel->pPrior;
|
| + selectAddColumnTypeAndCollation(pParse, pTab->nCol, pTab->aCol, pSel);
|
| + }
|
| + }
|
| + }
|
| + return WRC_Continue;
|
| +}
|
| +#endif
|
| +
|
| +
|
| +/*
|
| +** This routine adds datatype and collating sequence information to
|
| +** the Table structures of all FROM-clause subqueries in a
|
| +** SELECT statement.
|
| +**
|
| +** Use this routine after name resolution.
|
| +*/
|
| +static void sqlite3SelectAddTypeInfo(Parse *pParse, Select *pSelect){
|
| +#ifndef SQLITE_OMIT_SUBQUERY
|
| + Walker w;
|
| + w.xSelectCallback = selectAddSubqueryTypeInfo;
|
| + w.xExprCallback = exprWalkNoop;
|
| + w.pParse = pParse;
|
| + sqlite3WalkSelect(&w, pSelect);
|
| +#endif
|
| +}
|
| +
|
| +
|
| +/*
|
| +** This routine sets of a SELECT statement for processing. The
|
| +** following is accomplished:
|
| +**
|
| +** * VDBE Cursor numbers are assigned to all FROM-clause terms.
|
| +** * Ephemeral Table objects are created for all FROM-clause subqueries.
|
| +** * ON and USING clauses are shifted into WHERE statements
|
| +** * Wildcards "*" and "TABLE.*" in result sets are expanded.
|
| +** * Identifiers in expression are matched to tables.
|
| +**
|
| +** This routine acts recursively on all subqueries within the SELECT.
|
| +*/
|
| +void sqlite3SelectPrep(
|
| + Parse *pParse, /* The parser context */
|
| + Select *p, /* The SELECT statement being coded. */
|
| + NameContext *pOuterNC /* Name context for container */
|
| +){
|
| + sqlite3 *db;
|
| + if( NEVER(p==0) ) return;
|
| + db = pParse->db;
|
| + if( p->selFlags & SF_HasTypeInfo ) return;
|
| + sqlite3SelectExpand(pParse, p);
|
| + if( pParse->nErr || db->mallocFailed ) return;
|
| + sqlite3ResolveSelectNames(pParse, p, pOuterNC);
|
| + if( pParse->nErr || db->mallocFailed ) return;
|
| + sqlite3SelectAddTypeInfo(pParse, p);
|
| +}
|
| +
|
| +/*
|
| +** Reset the aggregate accumulator.
|
| +**
|
| +** The aggregate accumulator is a set of memory cells that hold
|
| +** intermediate results while calculating an aggregate. This
|
| +** routine simply stores NULLs in all of those memory cells.
|
| +*/
|
| +static void resetAccumulator(Parse *pParse, AggInfo *pAggInfo){
|
| + Vdbe *v = pParse->pVdbe;
|
| + int i;
|
| + struct AggInfo_func *pFunc;
|
| + if( pAggInfo->nFunc+pAggInfo->nColumn==0 ){
|
| + return;
|
| + }
|
| + for(i=0; i<pAggInfo->nColumn; i++){
|
| + sqlite3VdbeAddOp2(v, OP_Null, 0, pAggInfo->aCol[i].iMem);
|
| + }
|
| + for(pFunc=pAggInfo->aFunc, i=0; i<pAggInfo->nFunc; i++, pFunc++){
|
| + sqlite3VdbeAddOp2(v, OP_Null, 0, pFunc->iMem);
|
| + if( pFunc->iDistinct>=0 ){
|
| + Expr *pE = pFunc->pExpr;
|
| + assert( !ExprHasProperty(pE, EP_xIsSelect) );
|
| + if( pE->x.pList==0 || pE->x.pList->nExpr!=1 ){
|
| + sqlite3ErrorMsg(pParse, "DISTINCT aggregates must have exactly one "
|
| + "argument");
|
| + pFunc->iDistinct = -1;
|
| + }else{
|
| + KeyInfo *pKeyInfo = keyInfoFromExprList(pParse, pE->x.pList);
|
| + sqlite3VdbeAddOp4(v, OP_OpenEphemeral, pFunc->iDistinct, 0, 0,
|
| + (char*)pKeyInfo, P4_KEYINFO_HANDOFF);
|
| + }
|
| + }
|
| + }
|
| +}
|
| +
|
| +/*
|
| +** Invoke the OP_AggFinalize opcode for every aggregate function
|
| +** in the AggInfo structure.
|
| +*/
|
| +static void finalizeAggFunctions(Parse *pParse, AggInfo *pAggInfo){
|
| + Vdbe *v = pParse->pVdbe;
|
| + int i;
|
| + struct AggInfo_func *pF;
|
| + for(i=0, pF=pAggInfo->aFunc; i<pAggInfo->nFunc; i++, pF++){
|
| + ExprList *pList = pF->pExpr->x.pList;
|
| + assert( !ExprHasProperty(pF->pExpr, EP_xIsSelect) );
|
| + sqlite3VdbeAddOp4(v, OP_AggFinal, pF->iMem, pList ? pList->nExpr : 0, 0,
|
| + (void*)pF->pFunc, P4_FUNCDEF);
|
| + }
|
| +}
|
| +
|
| +/*
|
| +** Update the accumulator memory cells for an aggregate based on
|
| +** the current cursor position.
|
| +*/
|
| +static void updateAccumulator(Parse *pParse, AggInfo *pAggInfo){
|
| + Vdbe *v = pParse->pVdbe;
|
| + int i;
|
| + struct AggInfo_func *pF;
|
| + struct AggInfo_col *pC;
|
| +
|
| + pAggInfo->directMode = 1;
|
| + sqlite3ExprCacheClear(pParse);
|
| + for(i=0, pF=pAggInfo->aFunc; i<pAggInfo->nFunc; i++, pF++){
|
| + int nArg;
|
| + int addrNext = 0;
|
| + int regAgg;
|
| + ExprList *pList = pF->pExpr->x.pList;
|
| + assert( !ExprHasProperty(pF->pExpr, EP_xIsSelect) );
|
| + if( pList ){
|
| + nArg = pList->nExpr;
|
| + regAgg = sqlite3GetTempRange(pParse, nArg);
|
| + sqlite3ExprCodeExprList(pParse, pList, regAgg, 1);
|
| + }else{
|
| + nArg = 0;
|
| + regAgg = 0;
|
| + }
|
| + if( pF->iDistinct>=0 ){
|
| + addrNext = sqlite3VdbeMakeLabel(v);
|
| + assert( nArg==1 );
|
| + codeDistinct(pParse, pF->iDistinct, addrNext, 1, regAgg);
|
| + }
|
| + if( pF->pFunc->flags & SQLITE_FUNC_NEEDCOLL ){
|
| + CollSeq *pColl = 0;
|
| + struct ExprList_item *pItem;
|
| + int j;
|
| + assert( pList!=0 ); /* pList!=0 if pF->pFunc has NEEDCOLL */
|
| + for(j=0, pItem=pList->a; !pColl && j<nArg; j++, pItem++){
|
| + pColl = sqlite3ExprCollSeq(pParse, pItem->pExpr);
|
| + }
|
| + if( !pColl ){
|
| + pColl = pParse->db->pDfltColl;
|
| + }
|
| + sqlite3VdbeAddOp4(v, OP_CollSeq, 0, 0, 0, (char *)pColl, P4_COLLSEQ);
|
| + }
|
| + sqlite3VdbeAddOp4(v, OP_AggStep, 0, regAgg, pF->iMem,
|
| + (void*)pF->pFunc, P4_FUNCDEF);
|
| + sqlite3VdbeChangeP5(v, (u8)nArg);
|
| + sqlite3ExprCacheAffinityChange(pParse, regAgg, nArg);
|
| + sqlite3ReleaseTempRange(pParse, regAgg, nArg);
|
| + if( addrNext ){
|
| + sqlite3VdbeResolveLabel(v, addrNext);
|
| + sqlite3ExprCacheClear(pParse);
|
| + }
|
| + }
|
| +
|
| + /* Before populating the accumulator registers, clear the column cache.
|
| + ** Otherwise, if any of the required column values are already present
|
| + ** in registers, sqlite3ExprCode() may use OP_SCopy to copy the value
|
| + ** to pC->iMem. But by the time the value is used, the original register
|
| + ** may have been used, invalidating the underlying buffer holding the
|
| + ** text or blob value. See ticket [883034dcb5].
|
| + **
|
| + ** Another solution would be to change the OP_SCopy used to copy cached
|
| + ** values to an OP_Copy.
|
| + */
|
| + sqlite3ExprCacheClear(pParse);
|
| + for(i=0, pC=pAggInfo->aCol; i<pAggInfo->nAccumulator; i++, pC++){
|
| + sqlite3ExprCode(pParse, pC->pExpr, pC->iMem);
|
| + }
|
| + pAggInfo->directMode = 0;
|
| + sqlite3ExprCacheClear(pParse);
|
| +}
|
| +
|
| +/*
|
| +** Add a single OP_Explain instruction to the VDBE to explain a simple
|
| +** count(*) query ("SELECT count(*) FROM pTab").
|
| +*/
|
| +#ifndef SQLITE_OMIT_EXPLAIN
|
| +static void explainSimpleCount(
|
| + Parse *pParse, /* Parse context */
|
| + Table *pTab, /* Table being queried */
|
| + Index *pIdx /* Index used to optimize scan, or NULL */
|
| +){
|
| + if( pParse->explain==2 ){
|
| + char *zEqp = sqlite3MPrintf(pParse->db, "SCAN TABLE %s %s%s(~%d rows)",
|
| + pTab->zName,
|
| + pIdx ? "USING COVERING INDEX " : "",
|
| + pIdx ? pIdx->zName : "",
|
| + pTab->nRowEst
|
| + );
|
| + sqlite3VdbeAddOp4(
|
| + pParse->pVdbe, OP_Explain, pParse->iSelectId, 0, 0, zEqp, P4_DYNAMIC
|
| + );
|
| + }
|
| +}
|
| +#else
|
| +# define explainSimpleCount(a,b,c)
|
| +#endif
|
| +
|
| +/*
|
| +** Generate code for the SELECT statement given in the p argument.
|
| +**
|
| +** The results are distributed in various ways depending on the
|
| +** contents of the SelectDest structure pointed to by argument pDest
|
| +** as follows:
|
| +**
|
| +** pDest->eDest Result
|
| +** ------------ -------------------------------------------
|
| +** SRT_Output Generate a row of output (using the OP_ResultRow
|
| +** opcode) for each row in the result set.
|
| +**
|
| +** SRT_Mem Only valid if the result is a single column.
|
| +** Store the first column of the first result row
|
| +** in register pDest->iParm then abandon the rest
|
| +** of the query. This destination implies "LIMIT 1".
|
| +**
|
| +** SRT_Set The result must be a single column. Store each
|
| +** row of result as the key in table pDest->iParm.
|
| +** Apply the affinity pDest->affinity before storing
|
| +** results. Used to implement "IN (SELECT ...)".
|
| +**
|
| +** SRT_Union Store results as a key in a temporary table pDest->iParm.
|
| +**
|
| +** SRT_Except Remove results from the temporary table pDest->iParm.
|
| +**
|
| +** SRT_Table Store results in temporary table pDest->iParm.
|
| +** This is like SRT_EphemTab except that the table
|
| +** is assumed to already be open.
|
| +**
|
| +** SRT_EphemTab Create an temporary table pDest->iParm and store
|
| +** the result there. The cursor is left open after
|
| +** returning. This is like SRT_Table except that
|
| +** this destination uses OP_OpenEphemeral to create
|
| +** the table first.
|
| +**
|
| +** SRT_Coroutine Generate a co-routine that returns a new row of
|
| +** results each time it is invoked. The entry point
|
| +** of the co-routine is stored in register pDest->iParm.
|
| +**
|
| +** SRT_Exists Store a 1 in memory cell pDest->iParm if the result
|
| +** set is not empty.
|
| +**
|
| +** SRT_Discard Throw the results away. This is used by SELECT
|
| +** statements within triggers whose only purpose is
|
| +** the side-effects of functions.
|
| +**
|
| +** This routine returns the number of errors. If any errors are
|
| +** encountered, then an appropriate error message is left in
|
| +** pParse->zErrMsg.
|
| +**
|
| +** This routine does NOT free the Select structure passed in. The
|
| +** calling function needs to do that.
|
| +*/
|
| +int sqlite3Select(
|
| + Parse *pParse, /* The parser context */
|
| + Select *p, /* The SELECT statement being coded. */
|
| + SelectDest *pDest /* What to do with the query results */
|
| +){
|
| + int i, j; /* Loop counters */
|
| + WhereInfo *pWInfo; /* Return from sqlite3WhereBegin() */
|
| + Vdbe *v; /* The virtual machine under construction */
|
| + int isAgg; /* True for select lists like "count(*)" */
|
| + ExprList *pEList; /* List of columns to extract. */
|
| + SrcList *pTabList; /* List of tables to select from */
|
| + Expr *pWhere; /* The WHERE clause. May be NULL */
|
| + ExprList *pOrderBy; /* The ORDER BY clause. May be NULL */
|
| + ExprList *pGroupBy; /* The GROUP BY clause. May be NULL */
|
| + Expr *pHaving; /* The HAVING clause. May be NULL */
|
| + int isDistinct; /* True if the DISTINCT keyword is present */
|
| + int distinct; /* Table to use for the distinct set */
|
| + int rc = 1; /* Value to return from this function */
|
| + int addrSortIndex; /* Address of an OP_OpenEphemeral instruction */
|
| + AggInfo sAggInfo; /* Information used by aggregate queries */
|
| + int iEnd; /* Address of the end of the query */
|
| + sqlite3 *db; /* The database connection */
|
| +
|
| +#ifndef SQLITE_OMIT_EXPLAIN
|
| + int iRestoreSelectId = pParse->iSelectId;
|
| + pParse->iSelectId = pParse->iNextSelectId++;
|
| +#endif
|
| +
|
| + db = pParse->db;
|
| + if( p==0 || db->mallocFailed || pParse->nErr ){
|
| + return 1;
|
| + }
|
| + if( sqlite3AuthCheck(pParse, SQLITE_SELECT, 0, 0, 0) ) return 1;
|
| + memset(&sAggInfo, 0, sizeof(sAggInfo));
|
| +
|
| + if( IgnorableOrderby(pDest) ){
|
| + assert(pDest->eDest==SRT_Exists || pDest->eDest==SRT_Union ||
|
| + pDest->eDest==SRT_Except || pDest->eDest==SRT_Discard);
|
| + /* If ORDER BY makes no difference in the output then neither does
|
| + ** DISTINCT so it can be removed too. */
|
| + sqlite3ExprListDelete(db, p->pOrderBy);
|
| + p->pOrderBy = 0;
|
| + p->selFlags &= ~SF_Distinct;
|
| + }
|
| + sqlite3SelectPrep(pParse, p, 0);
|
| + pOrderBy = p->pOrderBy;
|
| + pTabList = p->pSrc;
|
| + pEList = p->pEList;
|
| + if( pParse->nErr || db->mallocFailed ){
|
| + goto select_end;
|
| + }
|
| + isAgg = (p->selFlags & SF_Aggregate)!=0;
|
| + assert( pEList!=0 );
|
| +
|
| + /* Begin generating code.
|
| + */
|
| + v = sqlite3GetVdbe(pParse);
|
| + if( v==0 ) goto select_end;
|
| +
|
| + /* If writing to memory or generating a set
|
| + ** only a single column may be output.
|
| + */
|
| +#ifndef SQLITE_OMIT_SUBQUERY
|
| + if( checkForMultiColumnSelectError(pParse, pDest, pEList->nExpr) ){
|
| + goto select_end;
|
| + }
|
| +#endif
|
| +
|
| + /* Generate code for all sub-queries in the FROM clause
|
| + */
|
| +#if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
|
| + for(i=0; !p->pPrior && i<pTabList->nSrc; i++){
|
| + struct SrcList_item *pItem = &pTabList->a[i];
|
| + SelectDest dest;
|
| + Select *pSub = pItem->pSelect;
|
| + int isAggSub;
|
| +
|
| + if( pSub==0 || pItem->isPopulated ) continue;
|
| +
|
| + /* Increment Parse.nHeight by the height of the largest expression
|
| + ** tree refered to by this, the parent select. The child select
|
| + ** may contain expression trees of at most
|
| + ** (SQLITE_MAX_EXPR_DEPTH-Parse.nHeight) height. This is a bit
|
| + ** more conservative than necessary, but much easier than enforcing
|
| + ** an exact limit.
|
| + */
|
| + pParse->nHeight += sqlite3SelectExprHeight(p);
|
| +
|
| + /* Check to see if the subquery can be absorbed into the parent. */
|
| + isAggSub = (pSub->selFlags & SF_Aggregate)!=0;
|
| + if( flattenSubquery(pParse, p, i, isAgg, isAggSub) ){
|
| + if( isAggSub ){
|
| + isAgg = 1;
|
| + p->selFlags |= SF_Aggregate;
|
| + }
|
| + i = -1;
|
| + }else{
|
| + sqlite3SelectDestInit(&dest, SRT_EphemTab, pItem->iCursor);
|
| + assert( pItem->isPopulated==0 );
|
| + explainSetInteger(pItem->iSelectId, (u8)pParse->iNextSelectId);
|
| + sqlite3Select(pParse, pSub, &dest);
|
| + pItem->isPopulated = 1;
|
| + pItem->pTab->nRowEst = (unsigned)pSub->nSelectRow;
|
| + }
|
| + if( /*pParse->nErr ||*/ db->mallocFailed ){
|
| + goto select_end;
|
| + }
|
| + pParse->nHeight -= sqlite3SelectExprHeight(p);
|
| + pTabList = p->pSrc;
|
| + if( !IgnorableOrderby(pDest) ){
|
| + pOrderBy = p->pOrderBy;
|
| + }
|
| + }
|
| + pEList = p->pEList;
|
| +#endif
|
| + pWhere = p->pWhere;
|
| + pGroupBy = p->pGroupBy;
|
| + pHaving = p->pHaving;
|
| + isDistinct = (p->selFlags & SF_Distinct)!=0;
|
| +
|
| +#ifndef SQLITE_OMIT_COMPOUND_SELECT
|
| + /* If there is are a sequence of queries, do the earlier ones first.
|
| + */
|
| + if( p->pPrior ){
|
| + if( p->pRightmost==0 ){
|
| + Select *pLoop, *pRight = 0;
|
| + int cnt = 0;
|
| + int mxSelect;
|
| + for(pLoop=p; pLoop; pLoop=pLoop->pPrior, cnt++){
|
| + pLoop->pRightmost = p;
|
| + pLoop->pNext = pRight;
|
| + pRight = pLoop;
|
| + }
|
| + mxSelect = db->aLimit[SQLITE_LIMIT_COMPOUND_SELECT];
|
| + if( mxSelect && cnt>mxSelect ){
|
| + sqlite3ErrorMsg(pParse, "too many terms in compound SELECT");
|
| + goto select_end;
|
| + }
|
| + }
|
| + rc = multiSelect(pParse, p, pDest);
|
| + explainSetInteger(pParse->iSelectId, iRestoreSelectId);
|
| + return rc;
|
| + }
|
| +#endif
|
| +
|
| + /* If possible, rewrite the query to use GROUP BY instead of DISTINCT.
|
| + ** GROUP BY might use an index, DISTINCT never does.
|
| + */
|
| + assert( p->pGroupBy==0 || (p->selFlags & SF_Aggregate)!=0 );
|
| + if( (p->selFlags & (SF_Distinct|SF_Aggregate))==SF_Distinct ){
|
| + p->pGroupBy = sqlite3ExprListDup(db, p->pEList, 0);
|
| + pGroupBy = p->pGroupBy;
|
| + p->selFlags &= ~SF_Distinct;
|
| + }
|
| +
|
| + /* If there is both a GROUP BY and an ORDER BY clause and they are
|
| + ** identical, then disable the ORDER BY clause since the GROUP BY
|
| + ** will cause elements to come out in the correct order. This is
|
| + ** an optimization - the correct answer should result regardless.
|
| + ** Use the SQLITE_GroupByOrder flag with SQLITE_TESTCTRL_OPTIMIZER
|
| + ** to disable this optimization for testing purposes.
|
| + */
|
| + if( sqlite3ExprListCompare(p->pGroupBy, pOrderBy)==0
|
| + && (db->flags & SQLITE_GroupByOrder)==0 ){
|
| + pOrderBy = 0;
|
| + }
|
| +
|
| + /* If there is an ORDER BY clause, then this sorting
|
| + ** index might end up being unused if the data can be
|
| + ** extracted in pre-sorted order. If that is the case, then the
|
| + ** OP_OpenEphemeral instruction will be changed to an OP_Noop once
|
| + ** we figure out that the sorting index is not needed. The addrSortIndex
|
| + ** variable is used to facilitate that change.
|
| + */
|
| + if( pOrderBy ){
|
| + KeyInfo *pKeyInfo;
|
| + pKeyInfo = keyInfoFromExprList(pParse, pOrderBy);
|
| + pOrderBy->iECursor = pParse->nTab++;
|
| + p->addrOpenEphm[2] = addrSortIndex =
|
| + sqlite3VdbeAddOp4(v, OP_OpenEphemeral,
|
| + pOrderBy->iECursor, pOrderBy->nExpr+2, 0,
|
| + (char*)pKeyInfo, P4_KEYINFO_HANDOFF);
|
| + }else{
|
| + addrSortIndex = -1;
|
| + }
|
| +
|
| + /* If the output is destined for a temporary table, open that table.
|
| + */
|
| + if( pDest->eDest==SRT_EphemTab ){
|
| + sqlite3VdbeAddOp2(v, OP_OpenEphemeral, pDest->iParm, pEList->nExpr);
|
| + }
|
| +
|
| + /* Set the limiter.
|
| + */
|
| + iEnd = sqlite3VdbeMakeLabel(v);
|
| + p->nSelectRow = (double)LARGEST_INT64;
|
| + computeLimitRegisters(pParse, p, iEnd);
|
| +
|
| + /* Open a virtual index to use for the distinct set.
|
| + */
|
| + if( p->selFlags & SF_Distinct ){
|
| + KeyInfo *pKeyInfo;
|
| + assert( isAgg || pGroupBy );
|
| + distinct = pParse->nTab++;
|
| + pKeyInfo = keyInfoFromExprList(pParse, p->pEList);
|
| + sqlite3VdbeAddOp4(v, OP_OpenEphemeral, distinct, 0, 0,
|
| + (char*)pKeyInfo, P4_KEYINFO_HANDOFF);
|
| + sqlite3VdbeChangeP5(v, BTREE_UNORDERED);
|
| + }else{
|
| + distinct = -1;
|
| + }
|
| +
|
| + /* Aggregate and non-aggregate queries are handled differently */
|
| + if( !isAgg && pGroupBy==0 ){
|
| + /* This case is for non-aggregate queries
|
| + ** Begin the database scan
|
| + */
|
| + pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, &pOrderBy, 0);
|
| + if( pWInfo==0 ) goto select_end;
|
| + if( pWInfo->nRowOut < p->nSelectRow ) p->nSelectRow = pWInfo->nRowOut;
|
| +
|
| + /* If sorting index that was created by a prior OP_OpenEphemeral
|
| + ** instruction ended up not being needed, then change the OP_OpenEphemeral
|
| + ** into an OP_Noop.
|
| + */
|
| + if( addrSortIndex>=0 && pOrderBy==0 ){
|
| + sqlite3VdbeChangeToNoop(v, addrSortIndex, 1);
|
| + p->addrOpenEphm[2] = -1;
|
| + }
|
| +
|
| + /* Use the standard inner loop
|
| + */
|
| + assert(!isDistinct);
|
| + selectInnerLoop(pParse, p, pEList, 0, 0, pOrderBy, -1, pDest,
|
| + pWInfo->iContinue, pWInfo->iBreak);
|
| +
|
| + /* End the database scan loop.
|
| + */
|
| + sqlite3WhereEnd(pWInfo);
|
| + }else{
|
| + /* This is the processing for aggregate queries */
|
| + NameContext sNC; /* Name context for processing aggregate information */
|
| + int iAMem; /* First Mem address for storing current GROUP BY */
|
| + int iBMem; /* First Mem address for previous GROUP BY */
|
| + int iUseFlag; /* Mem address holding flag indicating that at least
|
| + ** one row of the input to the aggregator has been
|
| + ** processed */
|
| + int iAbortFlag; /* Mem address which causes query abort if positive */
|
| + int groupBySort; /* Rows come from source in GROUP BY order */
|
| + int addrEnd; /* End of processing for this SELECT */
|
| +
|
| + /* Remove any and all aliases between the result set and the
|
| + ** GROUP BY clause.
|
| + */
|
| + if( pGroupBy ){
|
| + int k; /* Loop counter */
|
| + struct ExprList_item *pItem; /* For looping over expression in a list */
|
| +
|
| + for(k=p->pEList->nExpr, pItem=p->pEList->a; k>0; k--, pItem++){
|
| + pItem->iAlias = 0;
|
| + }
|
| + for(k=pGroupBy->nExpr, pItem=pGroupBy->a; k>0; k--, pItem++){
|
| + pItem->iAlias = 0;
|
| + }
|
| + if( p->nSelectRow>(double)100 ) p->nSelectRow = (double)100;
|
| + }else{
|
| + p->nSelectRow = (double)1;
|
| + }
|
| +
|
| +
|
| + /* Create a label to jump to when we want to abort the query */
|
| + addrEnd = sqlite3VdbeMakeLabel(v);
|
| +
|
| + /* Convert TK_COLUMN nodes into TK_AGG_COLUMN and make entries in
|
| + ** sAggInfo for all TK_AGG_FUNCTION nodes in expressions of the
|
| + ** SELECT statement.
|
| + */
|
| + memset(&sNC, 0, sizeof(sNC));
|
| + sNC.pParse = pParse;
|
| + sNC.pSrcList = pTabList;
|
| + sNC.pAggInfo = &sAggInfo;
|
| + sAggInfo.nSortingColumn = pGroupBy ? pGroupBy->nExpr+1 : 0;
|
| + sAggInfo.pGroupBy = pGroupBy;
|
| + sqlite3ExprAnalyzeAggList(&sNC, pEList);
|
| + sqlite3ExprAnalyzeAggList(&sNC, pOrderBy);
|
| + if( pHaving ){
|
| + sqlite3ExprAnalyzeAggregates(&sNC, pHaving);
|
| + }
|
| + sAggInfo.nAccumulator = sAggInfo.nColumn;
|
| + for(i=0; i<sAggInfo.nFunc; i++){
|
| + assert( !ExprHasProperty(sAggInfo.aFunc[i].pExpr, EP_xIsSelect) );
|
| + sqlite3ExprAnalyzeAggList(&sNC, sAggInfo.aFunc[i].pExpr->x.pList);
|
| + }
|
| + if( db->mallocFailed ) goto select_end;
|
| +
|
| + /* Processing for aggregates with GROUP BY is very different and
|
| + ** much more complex than aggregates without a GROUP BY.
|
| + */
|
| + if( pGroupBy ){
|
| + KeyInfo *pKeyInfo; /* Keying information for the group by clause */
|
| + int j1; /* A-vs-B comparision jump */
|
| + int addrOutputRow; /* Start of subroutine that outputs a result row */
|
| + int regOutputRow; /* Return address register for output subroutine */
|
| + int addrSetAbort; /* Set the abort flag and return */
|
| + int addrTopOfLoop; /* Top of the input loop */
|
| + int addrSortingIdx; /* The OP_OpenEphemeral for the sorting index */
|
| + int addrReset; /* Subroutine for resetting the accumulator */
|
| + int regReset; /* Return address register for reset subroutine */
|
| +
|
| + /* If there is a GROUP BY clause we might need a sorting index to
|
| + ** implement it. Allocate that sorting index now. If it turns out
|
| + ** that we do not need it after all, the OpenEphemeral instruction
|
| + ** will be converted into a Noop.
|
| + */
|
| + sAggInfo.sortingIdx = pParse->nTab++;
|
| + pKeyInfo = keyInfoFromExprList(pParse, pGroupBy);
|
| + addrSortingIdx = sqlite3VdbeAddOp4(v, OP_OpenEphemeral,
|
| + sAggInfo.sortingIdx, sAggInfo.nSortingColumn,
|
| + 0, (char*)pKeyInfo, P4_KEYINFO_HANDOFF);
|
| +
|
| + /* Initialize memory locations used by GROUP BY aggregate processing
|
| + */
|
| + iUseFlag = ++pParse->nMem;
|
| + iAbortFlag = ++pParse->nMem;
|
| + regOutputRow = ++pParse->nMem;
|
| + addrOutputRow = sqlite3VdbeMakeLabel(v);
|
| + regReset = ++pParse->nMem;
|
| + addrReset = sqlite3VdbeMakeLabel(v);
|
| + iAMem = pParse->nMem + 1;
|
| + pParse->nMem += pGroupBy->nExpr;
|
| + iBMem = pParse->nMem + 1;
|
| + pParse->nMem += pGroupBy->nExpr;
|
| + sqlite3VdbeAddOp2(v, OP_Integer, 0, iAbortFlag);
|
| + VdbeComment((v, "clear abort flag"));
|
| + sqlite3VdbeAddOp2(v, OP_Integer, 0, iUseFlag);
|
| + VdbeComment((v, "indicate accumulator empty"));
|
| +
|
| + /* Begin a loop that will extract all source rows in GROUP BY order.
|
| + ** This might involve two separate loops with an OP_Sort in between, or
|
| + ** it might be a single loop that uses an index to extract information
|
| + ** in the right order to begin with.
|
| + */
|
| + sqlite3VdbeAddOp2(v, OP_Gosub, regReset, addrReset);
|
| + pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, &pGroupBy, 0);
|
| + if( pWInfo==0 ) goto select_end;
|
| + if( pGroupBy==0 ){
|
| + /* The optimizer is able to deliver rows in group by order so
|
| + ** we do not have to sort. The OP_OpenEphemeral table will be
|
| + ** cancelled later because we still need to use the pKeyInfo
|
| + */
|
| + pGroupBy = p->pGroupBy;
|
| + groupBySort = 0;
|
| + }else{
|
| + /* Rows are coming out in undetermined order. We have to push
|
| + ** each row into a sorting index, terminate the first loop,
|
| + ** then loop over the sorting index in order to get the output
|
| + ** in sorted order
|
| + */
|
| + int regBase;
|
| + int regRecord;
|
| + int nCol;
|
| + int nGroupBy;
|
| +
|
| + explainTempTable(pParse,
|
| + isDistinct && !(p->selFlags&SF_Distinct)?"DISTINCT":"GROUP BY");
|
| +
|
| + groupBySort = 1;
|
| + nGroupBy = pGroupBy->nExpr;
|
| + nCol = nGroupBy + 1;
|
| + j = nGroupBy+1;
|
| + for(i=0; i<sAggInfo.nColumn; i++){
|
| + if( sAggInfo.aCol[i].iSorterColumn>=j ){
|
| + nCol++;
|
| + j++;
|
| + }
|
| + }
|
| + regBase = sqlite3GetTempRange(pParse, nCol);
|
| + sqlite3ExprCacheClear(pParse);
|
| + sqlite3ExprCodeExprList(pParse, pGroupBy, regBase, 0);
|
| + sqlite3VdbeAddOp2(v, OP_Sequence, sAggInfo.sortingIdx,regBase+nGroupBy);
|
| + j = nGroupBy+1;
|
| + for(i=0; i<sAggInfo.nColumn; i++){
|
| + struct AggInfo_col *pCol = &sAggInfo.aCol[i];
|
| + if( pCol->iSorterColumn>=j ){
|
| + int r1 = j + regBase;
|
| + int r2;
|
| +
|
| + r2 = sqlite3ExprCodeGetColumn(pParse,
|
| + pCol->pTab, pCol->iColumn, pCol->iTable, r1);
|
| + if( r1!=r2 ){
|
| + sqlite3VdbeAddOp2(v, OP_SCopy, r2, r1);
|
| + }
|
| + j++;
|
| + }
|
| + }
|
| + regRecord = sqlite3GetTempReg(pParse);
|
| + sqlite3VdbeAddOp3(v, OP_MakeRecord, regBase, nCol, regRecord);
|
| + sqlite3VdbeAddOp2(v, OP_IdxInsert, sAggInfo.sortingIdx, regRecord);
|
| + sqlite3ReleaseTempReg(pParse, regRecord);
|
| + sqlite3ReleaseTempRange(pParse, regBase, nCol);
|
| + sqlite3WhereEnd(pWInfo);
|
| + sqlite3VdbeAddOp2(v, OP_Sort, sAggInfo.sortingIdx, addrEnd);
|
| + VdbeComment((v, "GROUP BY sort"));
|
| + sAggInfo.useSortingIdx = 1;
|
| + sqlite3ExprCacheClear(pParse);
|
| + }
|
| +
|
| + /* Evaluate the current GROUP BY terms and store in b0, b1, b2...
|
| + ** (b0 is memory location iBMem+0, b1 is iBMem+1, and so forth)
|
| + ** Then compare the current GROUP BY terms against the GROUP BY terms
|
| + ** from the previous row currently stored in a0, a1, a2...
|
| + */
|
| + addrTopOfLoop = sqlite3VdbeCurrentAddr(v);
|
| + sqlite3ExprCacheClear(pParse);
|
| + for(j=0; j<pGroupBy->nExpr; j++){
|
| + if( groupBySort ){
|
| + sqlite3VdbeAddOp3(v, OP_Column, sAggInfo.sortingIdx, j, iBMem+j);
|
| + }else{
|
| + sAggInfo.directMode = 1;
|
| + sqlite3ExprCode(pParse, pGroupBy->a[j].pExpr, iBMem+j);
|
| + }
|
| + }
|
| + sqlite3VdbeAddOp4(v, OP_Compare, iAMem, iBMem, pGroupBy->nExpr,
|
| + (char*)pKeyInfo, P4_KEYINFO);
|
| + j1 = sqlite3VdbeCurrentAddr(v);
|
| + sqlite3VdbeAddOp3(v, OP_Jump, j1+1, 0, j1+1);
|
| +
|
| + /* Generate code that runs whenever the GROUP BY changes.
|
| + ** Changes in the GROUP BY are detected by the previous code
|
| + ** block. If there were no changes, this block is skipped.
|
| + **
|
| + ** This code copies current group by terms in b0,b1,b2,...
|
| + ** over to a0,a1,a2. It then calls the output subroutine
|
| + ** and resets the aggregate accumulator registers in preparation
|
| + ** for the next GROUP BY batch.
|
| + */
|
| + sqlite3ExprCodeMove(pParse, iBMem, iAMem, pGroupBy->nExpr);
|
| + sqlite3VdbeAddOp2(v, OP_Gosub, regOutputRow, addrOutputRow);
|
| + VdbeComment((v, "output one row"));
|
| + sqlite3VdbeAddOp2(v, OP_IfPos, iAbortFlag, addrEnd);
|
| + VdbeComment((v, "check abort flag"));
|
| + sqlite3VdbeAddOp2(v, OP_Gosub, regReset, addrReset);
|
| + VdbeComment((v, "reset accumulator"));
|
| +
|
| + /* Update the aggregate accumulators based on the content of
|
| + ** the current row
|
| + */
|
| + sqlite3VdbeJumpHere(v, j1);
|
| + updateAccumulator(pParse, &sAggInfo);
|
| + sqlite3VdbeAddOp2(v, OP_Integer, 1, iUseFlag);
|
| + VdbeComment((v, "indicate data in accumulator"));
|
| +
|
| + /* End of the loop
|
| + */
|
| + if( groupBySort ){
|
| + sqlite3VdbeAddOp2(v, OP_Next, sAggInfo.sortingIdx, addrTopOfLoop);
|
| + }else{
|
| + sqlite3WhereEnd(pWInfo);
|
| + sqlite3VdbeChangeToNoop(v, addrSortingIdx, 1);
|
| + }
|
| +
|
| + /* Output the final row of result
|
| + */
|
| + sqlite3VdbeAddOp2(v, OP_Gosub, regOutputRow, addrOutputRow);
|
| + VdbeComment((v, "output final row"));
|
| +
|
| + /* Jump over the subroutines
|
| + */
|
| + sqlite3VdbeAddOp2(v, OP_Goto, 0, addrEnd);
|
| +
|
| + /* Generate a subroutine that outputs a single row of the result
|
| + ** set. This subroutine first looks at the iUseFlag. If iUseFlag
|
| + ** is less than or equal to zero, the subroutine is a no-op. If
|
| + ** the processing calls for the query to abort, this subroutine
|
| + ** increments the iAbortFlag memory location before returning in
|
| + ** order to signal the caller to abort.
|
| + */
|
| + addrSetAbort = sqlite3VdbeCurrentAddr(v);
|
| + sqlite3VdbeAddOp2(v, OP_Integer, 1, iAbortFlag);
|
| + VdbeComment((v, "set abort flag"));
|
| + sqlite3VdbeAddOp1(v, OP_Return, regOutputRow);
|
| + sqlite3VdbeResolveLabel(v, addrOutputRow);
|
| + addrOutputRow = sqlite3VdbeCurrentAddr(v);
|
| + sqlite3VdbeAddOp2(v, OP_IfPos, iUseFlag, addrOutputRow+2);
|
| + VdbeComment((v, "Groupby result generator entry point"));
|
| + sqlite3VdbeAddOp1(v, OP_Return, regOutputRow);
|
| + finalizeAggFunctions(pParse, &sAggInfo);
|
| + sqlite3ExprIfFalse(pParse, pHaving, addrOutputRow+1, SQLITE_JUMPIFNULL);
|
| + selectInnerLoop(pParse, p, p->pEList, 0, 0, pOrderBy,
|
| + distinct, pDest,
|
| + addrOutputRow+1, addrSetAbort);
|
| + sqlite3VdbeAddOp1(v, OP_Return, regOutputRow);
|
| + VdbeComment((v, "end groupby result generator"));
|
| +
|
| + /* Generate a subroutine that will reset the group-by accumulator
|
| + */
|
| + sqlite3VdbeResolveLabel(v, addrReset);
|
| + resetAccumulator(pParse, &sAggInfo);
|
| + sqlite3VdbeAddOp1(v, OP_Return, regReset);
|
| +
|
| + } /* endif pGroupBy. Begin aggregate queries without GROUP BY: */
|
| + else {
|
| + ExprList *pDel = 0;
|
| +#ifndef SQLITE_OMIT_BTREECOUNT
|
| + Table *pTab;
|
| + if( (pTab = isSimpleCount(p, &sAggInfo))!=0 ){
|
| + /* If isSimpleCount() returns a pointer to a Table structure, then
|
| + ** the SQL statement is of the form:
|
| + **
|
| + ** SELECT count(*) FROM <tbl>
|
| + **
|
| + ** where the Table structure returned represents table <tbl>.
|
| + **
|
| + ** This statement is so common that it is optimized specially. The
|
| + ** OP_Count instruction is executed either on the intkey table that
|
| + ** contains the data for table <tbl> or on one of its indexes. It
|
| + ** is better to execute the op on an index, as indexes are almost
|
| + ** always spread across less pages than their corresponding tables.
|
| + */
|
| + const int iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
|
| + const int iCsr = pParse->nTab++; /* Cursor to scan b-tree */
|
| + Index *pIdx; /* Iterator variable */
|
| + KeyInfo *pKeyInfo = 0; /* Keyinfo for scanned index */
|
| + Index *pBest = 0; /* Best index found so far */
|
| + int iRoot = pTab->tnum; /* Root page of scanned b-tree */
|
| +
|
| + sqlite3CodeVerifySchema(pParse, iDb);
|
| + sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName);
|
| +
|
| + /* Search for the index that has the least amount of columns. If
|
| + ** there is such an index, and it has less columns than the table
|
| + ** does, then we can assume that it consumes less space on disk and
|
| + ** will therefore be cheaper to scan to determine the query result.
|
| + ** In this case set iRoot to the root page number of the index b-tree
|
| + ** and pKeyInfo to the KeyInfo structure required to navigate the
|
| + ** index.
|
| + **
|
| + ** In practice the KeyInfo structure will not be used. It is only
|
| + ** passed to keep OP_OpenRead happy.
|
| + */
|
| + for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
|
| + if( !pBest || pIdx->nColumn<pBest->nColumn ){
|
| + pBest = pIdx;
|
| + }
|
| + }
|
| + if( pBest && pBest->nColumn<pTab->nCol ){
|
| + iRoot = pBest->tnum;
|
| + pKeyInfo = sqlite3IndexKeyinfo(pParse, pBest);
|
| + }
|
| +
|
| + /* Open a read-only cursor, execute the OP_Count, close the cursor. */
|
| + sqlite3VdbeAddOp3(v, OP_OpenRead, iCsr, iRoot, iDb);
|
| + if( pKeyInfo ){
|
| + sqlite3VdbeChangeP4(v, -1, (char *)pKeyInfo, P4_KEYINFO_HANDOFF);
|
| + }
|
| + sqlite3VdbeAddOp2(v, OP_Count, iCsr, sAggInfo.aFunc[0].iMem);
|
| + sqlite3VdbeAddOp1(v, OP_Close, iCsr);
|
| + explainSimpleCount(pParse, pTab, pBest);
|
| + }else
|
| +#endif /* SQLITE_OMIT_BTREECOUNT */
|
| + {
|
| + /* Check if the query is of one of the following forms:
|
| + **
|
| + ** SELECT min(x) FROM ...
|
| + ** SELECT max(x) FROM ...
|
| + **
|
| + ** If it is, then ask the code in where.c to attempt to sort results
|
| + ** as if there was an "ORDER ON x" or "ORDER ON x DESC" clause.
|
| + ** If where.c is able to produce results sorted in this order, then
|
| + ** add vdbe code to break out of the processing loop after the
|
| + ** first iteration (since the first iteration of the loop is
|
| + ** guaranteed to operate on the row with the minimum or maximum
|
| + ** value of x, the only row required).
|
| + **
|
| + ** A special flag must be passed to sqlite3WhereBegin() to slightly
|
| + ** modify behaviour as follows:
|
| + **
|
| + ** + If the query is a "SELECT min(x)", then the loop coded by
|
| + ** where.c should not iterate over any values with a NULL value
|
| + ** for x.
|
| + **
|
| + ** + The optimizer code in where.c (the thing that decides which
|
| + ** index or indices to use) should place a different priority on
|
| + ** satisfying the 'ORDER BY' clause than it does in other cases.
|
| + ** Refer to code and comments in where.c for details.
|
| + */
|
| + ExprList *pMinMax = 0;
|
| + u8 flag = minMaxQuery(p);
|
| + if( flag ){
|
| + assert( !ExprHasProperty(p->pEList->a[0].pExpr, EP_xIsSelect) );
|
| + pMinMax = sqlite3ExprListDup(db, p->pEList->a[0].pExpr->x.pList,0);
|
| + pDel = pMinMax;
|
| + if( pMinMax && !db->mallocFailed ){
|
| + pMinMax->a[0].sortOrder = flag!=WHERE_ORDERBY_MIN ?1:0;
|
| + pMinMax->a[0].pExpr->op = TK_COLUMN;
|
| + }
|
| + }
|
| +
|
| + /* This case runs if the aggregate has no GROUP BY clause. The
|
| + ** processing is much simpler since there is only a single row
|
| + ** of output.
|
| + */
|
| + resetAccumulator(pParse, &sAggInfo);
|
| + pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, &pMinMax, flag);
|
| + if( pWInfo==0 ){
|
| + sqlite3ExprListDelete(db, pDel);
|
| + goto select_end;
|
| + }
|
| + updateAccumulator(pParse, &sAggInfo);
|
| + if( !pMinMax && flag ){
|
| + sqlite3VdbeAddOp2(v, OP_Goto, 0, pWInfo->iBreak);
|
| + VdbeComment((v, "%s() by index",
|
| + (flag==WHERE_ORDERBY_MIN?"min":"max")));
|
| + }
|
| + sqlite3WhereEnd(pWInfo);
|
| + finalizeAggFunctions(pParse, &sAggInfo);
|
| + }
|
| +
|
| + pOrderBy = 0;
|
| + sqlite3ExprIfFalse(pParse, pHaving, addrEnd, SQLITE_JUMPIFNULL);
|
| + selectInnerLoop(pParse, p, p->pEList, 0, 0, 0, -1,
|
| + pDest, addrEnd, addrEnd);
|
| + sqlite3ExprListDelete(db, pDel);
|
| + }
|
| + sqlite3VdbeResolveLabel(v, addrEnd);
|
| +
|
| + } /* endif aggregate query */
|
| +
|
| + if( distinct>=0 ){
|
| + explainTempTable(pParse, "DISTINCT");
|
| + }
|
| +
|
| + /* If there is an ORDER BY clause, then we need to sort the results
|
| + ** and send them to the callback one by one.
|
| + */
|
| + if( pOrderBy ){
|
| + explainTempTable(pParse, "ORDER BY");
|
| + generateSortTail(pParse, p, v, pEList->nExpr, pDest);
|
| + }
|
| +
|
| + /* Jump here to skip this query
|
| + */
|
| + sqlite3VdbeResolveLabel(v, iEnd);
|
| +
|
| + /* The SELECT was successfully coded. Set the return code to 0
|
| + ** to indicate no errors.
|
| + */
|
| + rc = 0;
|
| +
|
| + /* Control jumps to here if an error is encountered above, or upon
|
| + ** successful coding of the SELECT.
|
| + */
|
| +select_end:
|
| + explainSetInteger(pParse->iSelectId, iRestoreSelectId);
|
| +
|
| + /* Identify column names if results of the SELECT are to be output.
|
| + */
|
| + if( rc==SQLITE_OK && pDest->eDest==SRT_Output ){
|
| + generateColumnNames(pParse, pTabList, pEList);
|
| + }
|
| +
|
| + sqlite3DbFree(db, sAggInfo.aCol);
|
| + sqlite3DbFree(db, sAggInfo.aFunc);
|
| + return rc;
|
| +}
|
| +
|
| +#if defined(SQLITE_DEBUG)
|
| +/*
|
| +*******************************************************************************
|
| +** The following code is used for testing and debugging only. The code
|
| +** that follows does not appear in normal builds.
|
| +**
|
| +** These routines are used to print out the content of all or part of a
|
| +** parse structures such as Select or Expr. Such printouts are useful
|
| +** for helping to understand what is happening inside the code generator
|
| +** during the execution of complex SELECT statements.
|
| +**
|
| +** These routine are not called anywhere from within the normal
|
| +** code base. Then are intended to be called from within the debugger
|
| +** or from temporary "printf" statements inserted for debugging.
|
| +*/
|
| +void sqlite3PrintExpr(Expr *p){
|
| + if( !ExprHasProperty(p, EP_IntValue) && p->u.zToken ){
|
| + sqlite3DebugPrintf("(%s", p->u.zToken);
|
| + }else{
|
| + sqlite3DebugPrintf("(%d", p->op);
|
| + }
|
| + if( p->pLeft ){
|
| + sqlite3DebugPrintf(" ");
|
| + sqlite3PrintExpr(p->pLeft);
|
| + }
|
| + if( p->pRight ){
|
| + sqlite3DebugPrintf(" ");
|
| + sqlite3PrintExpr(p->pRight);
|
| + }
|
| + sqlite3DebugPrintf(")");
|
| +}
|
| +void sqlite3PrintExprList(ExprList *pList){
|
| + int i;
|
| + for(i=0; i<pList->nExpr; i++){
|
| + sqlite3PrintExpr(pList->a[i].pExpr);
|
| + if( i<pList->nExpr-1 ){
|
| + sqlite3DebugPrintf(", ");
|
| + }
|
| + }
|
| +}
|
| +void sqlite3PrintSelect(Select *p, int indent){
|
| + sqlite3DebugPrintf("%*sSELECT(%p) ", indent, "", p);
|
| + sqlite3PrintExprList(p->pEList);
|
| + sqlite3DebugPrintf("\n");
|
| + if( p->pSrc ){
|
| + char *zPrefix;
|
| + int i;
|
| + zPrefix = "FROM";
|
| + for(i=0; i<p->pSrc->nSrc; i++){
|
| + struct SrcList_item *pItem = &p->pSrc->a[i];
|
| + sqlite3DebugPrintf("%*s ", indent+6, zPrefix);
|
| + zPrefix = "";
|
| + if( pItem->pSelect ){
|
| + sqlite3DebugPrintf("(\n");
|
| + sqlite3PrintSelect(pItem->pSelect, indent+10);
|
| + sqlite3DebugPrintf("%*s)", indent+8, "");
|
| + }else if( pItem->zName ){
|
| + sqlite3DebugPrintf("%s", pItem->zName);
|
| + }
|
| + if( pItem->pTab ){
|
| + sqlite3DebugPrintf("(table: %s)", pItem->pTab->zName);
|
| + }
|
| + if( pItem->zAlias ){
|
| + sqlite3DebugPrintf(" AS %s", pItem->zAlias);
|
| + }
|
| + if( i<p->pSrc->nSrc-1 ){
|
| + sqlite3DebugPrintf(",");
|
| + }
|
| + sqlite3DebugPrintf("\n");
|
| + }
|
| + }
|
| + if( p->pWhere ){
|
| + sqlite3DebugPrintf("%*s WHERE ", indent, "");
|
| + sqlite3PrintExpr(p->pWhere);
|
| + sqlite3DebugPrintf("\n");
|
| + }
|
| + if( p->pGroupBy ){
|
| + sqlite3DebugPrintf("%*s GROUP BY ", indent, "");
|
| + sqlite3PrintExprList(p->pGroupBy);
|
| + sqlite3DebugPrintf("\n");
|
| + }
|
| + if( p->pHaving ){
|
| + sqlite3DebugPrintf("%*s HAVING ", indent, "");
|
| + sqlite3PrintExpr(p->pHaving);
|
| + sqlite3DebugPrintf("\n");
|
| + }
|
| + if( p->pOrderBy ){
|
| + sqlite3DebugPrintf("%*s ORDER BY ", indent, "");
|
| + sqlite3PrintExprList(p->pOrderBy);
|
| + sqlite3DebugPrintf("\n");
|
| + }
|
| +}
|
| +/* End of the structure debug printing code
|
| +*****************************************************************************/
|
| +#endif /* defined(SQLITE_TEST) || defined(SQLITE_DEBUG) */
|
|
|
Chromium Code Reviews
Issue 694353003:
Get `gn gen` to succeed on Windows (Closed)
Base URL: https://github.com/domokit/mojo.git@master