diff options
Diffstat (limited to 'src/select.c')
| -rw-r--r-- | src/select.c | 508 |
1 files changed, 356 insertions, 152 deletions
diff --git a/src/select.c b/src/select.c index 6ec9da3..f3f1490 100644 --- a/src/select.c +++ b/src/select.c @@ -55,7 +55,7 @@ Select *sqlite3SelectNew( 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 */ + u16 selFlags, /* Flag parameters, such as SF_Distinct */ Expr *pLimit, /* LIMIT value. NULL means not used */ Expr *pOffset /* OFFSET value. NULL means no offset */ ){ @@ -79,7 +79,7 @@ Select *sqlite3SelectNew( pNew->pGroupBy = pGroupBy; pNew->pHaving = pHaving; pNew->pOrderBy = pOrderBy; - pNew->selFlags = isDistinct ? SF_Distinct : 0; + pNew->selFlags = selFlags; pNew->op = TK_SELECT; pNew->pLimit = pLimit; pNew->pOffset = pOffset; @@ -526,6 +526,19 @@ static int checkForMultiColumnSelectError( #endif /* +** An instance of the following object is used to record information about +** how to process the DISTINCT keyword, to simplify passing that information +** into the selectInnerLoop() routine. +*/ +typedef struct DistinctCtx DistinctCtx; +struct DistinctCtx { + u8 isTnct; /* True if the DISTINCT keyword is present */ + u8 eTnctType; /* One of the WHERE_DISTINCT_* operators */ + int tabTnct; /* Ephemeral table used for DISTINCT processing */ + int addrTnct; /* Address of OP_OpenEphemeral opcode for tabTnct */ +}; + +/* ** This routine generates the code for the inside of the inner loop ** of a SELECT. ** @@ -541,7 +554,7 @@ static void selectInnerLoop( 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 */ + DistinctCtx *pDistinct, /* If not NULL, info on how to process 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 */ @@ -557,7 +570,7 @@ static void selectInnerLoop( assert( v ); if( NEVER(v==0) ) return; assert( pEList!=0 ); - hasDistinct = distinct>=0; + hasDistinct = pDistinct ? pDistinct->eTnctType : WHERE_DISTINCT_NOOP; if( pOrderBy==0 && !hasDistinct ){ codeOffset(v, p, iContinue); } @@ -597,7 +610,55 @@ static void selectInnerLoop( if( hasDistinct ){ assert( pEList!=0 ); assert( pEList->nExpr==nColumn ); - codeDistinct(pParse, distinct, iContinue, nColumn, regResult); + switch( pDistinct->eTnctType ){ + case WHERE_DISTINCT_ORDERED: { + VdbeOp *pOp; /* No longer required OpenEphemeral instr. */ + int iJump; /* Jump destination */ + int regPrev; /* Previous row content */ + + /* Allocate space for the previous row */ + regPrev = pParse->nMem+1; + pParse->nMem += nColumn; + + /* Change the OP_OpenEphemeral coded earlier to an OP_Null + ** sets the MEM_Cleared bit on the first register of the + ** previous value. This will cause the OP_Ne below to always + ** fail on the first iteration of the loop even if the first + ** row is all NULLs. + */ + sqlite3VdbeChangeToNoop(v, pDistinct->addrTnct); + pOp = sqlite3VdbeGetOp(v, pDistinct->addrTnct); + pOp->opcode = OP_Null; + pOp->p1 = 1; + pOp->p2 = regPrev; + + iJump = sqlite3VdbeCurrentAddr(v) + nColumn; + for(i=0; i<nColumn; i++){ + CollSeq *pColl = sqlite3ExprCollSeq(pParse, pEList->a[i].pExpr); + if( i<nColumn-1 ){ + sqlite3VdbeAddOp3(v, OP_Ne, regResult+i, iJump, regPrev+i); + }else{ + sqlite3VdbeAddOp3(v, OP_Eq, regResult+i, iContinue, regPrev+i); + } + sqlite3VdbeChangeP4(v, -1, (const char *)pColl, P4_COLLSEQ); + sqlite3VdbeChangeP5(v, SQLITE_NULLEQ); + } + assert( sqlite3VdbeCurrentAddr(v)==iJump ); + sqlite3VdbeAddOp3(v, OP_Copy, regResult, regPrev, nColumn-1); + break; + } + + case WHERE_DISTINCT_UNIQUE: { + sqlite3VdbeChangeToNoop(v, pDistinct->addrTnct); + break; + } + + default: { + assert( pDistinct->eTnctType==WHERE_DISTINCT_UNORDERED ); + codeDistinct(pParse, pDistinct->tabTnct, iContinue, nColumn, regResult); + break; + } + } if( pOrderBy==0 ){ codeOffset(v, p, iContinue); } @@ -655,7 +716,8 @@ static void selectInnerLoop( */ case SRT_Set: { assert( nColumn==1 ); - p->affinity = sqlite3CompareAffinity(pEList->a[0].pExpr, pDest->affSdst); + pDest->affSdst = + sqlite3CompareAffinity(pEList->a[0].pExpr, pDest->affSdst); 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 @@ -664,7 +726,7 @@ static void selectInnerLoop( pushOntoSorter(pParse, pOrderBy, p, regResult); }else{ int r1 = sqlite3GetTempReg(pParse); - sqlite3VdbeAddOp4(v, OP_MakeRecord, regResult, 1, r1, &p->affinity, 1); + sqlite3VdbeAddOp4(v, OP_MakeRecord, regResult,1,r1, &pDest->affSdst, 1); sqlite3ExprCacheAffinityChange(pParse, regResult, 1); sqlite3VdbeAddOp2(v, OP_IdxInsert, iParm, r1); sqlite3ReleaseTempReg(pParse, r1); @@ -931,7 +993,8 @@ static void generateSortTail( #ifndef SQLITE_OMIT_SUBQUERY case SRT_Set: { assert( nColumn==1 ); - sqlite3VdbeAddOp4(v, OP_MakeRecord, regRow, 1, regRowid, &p->affinity, 1); + sqlite3VdbeAddOp4(v, OP_MakeRecord, regRow, 1, regRowid, + &pDest->affSdst, 1); sqlite3ExprCacheAffinityChange(pParse, regRow, 1); sqlite3VdbeAddOp2(v, OP_IdxInsert, iParm, regRowid); break; @@ -1246,7 +1309,7 @@ static void generateColumnNames( 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 */ + i16 *pnCol, /* Write the number of columns here */ Column **paCol /* Write the new column list here */ ){ sqlite3 *db = pParse->db; /* Database connection */ @@ -1272,9 +1335,7 @@ static int selectColumnsFromExprList( 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 ); + p = sqlite3ExprSkipCollate(pEList->a[i].pExpr); if( (zName = pEList->a[i].zName)!=0 ){ /* If the column contains an "AS <name>" phrase, use <name> as the name */ zName = sqlite3DbStrDup(db, zName); @@ -1312,6 +1373,9 @@ static int selectColumnsFromExprList( for(j=cnt=0; j<i; j++){ if( sqlite3StrICmp(aCol[j].zName, zName)==0 ){ char *zNewName; + int k; + for(k=nName-1; k>1 && sqlite3Isdigit(zName[k]); k--){} + if( zName[k]==':' ) nName = k; zName[nName] = 0; zNewName = sqlite3MPrintf(db, "%s:%d", zName, ++cnt); sqlite3DbFree(db, zName); @@ -1643,6 +1707,8 @@ static int multiSelect( int addr = 0; int nLimit; assert( !pPrior->pLimit ); + pPrior->iLimit = p->iLimit; + pPrior->iOffset = p->iOffset; pPrior->pLimit = p->pLimit; pPrior->pOffset = p->pOffset; explainSetInteger(iSub1, pParse->iNextSelectId); @@ -1768,7 +1834,7 @@ static int multiSelect( sqlite3VdbeAddOp2(v, OP_Rewind, unionTab, iBreak); iStart = sqlite3VdbeCurrentAddr(v); selectInnerLoop(pParse, p, p->pEList, unionTab, p->pEList->nExpr, - 0, -1, &dest, iCont, iBreak); + 0, 0, &dest, iCont, iBreak); sqlite3VdbeResolveLabel(v, iCont); sqlite3VdbeAddOp2(v, OP_Next, unionTab, iStart); sqlite3VdbeResolveLabel(v, iBreak); @@ -1846,7 +1912,7 @@ static int multiSelect( 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); + 0, 0, &dest, iCont, iBreak); sqlite3VdbeResolveLabel(v, iCont); sqlite3VdbeAddOp2(v, OP_Next, tab1, iStart); sqlite3VdbeResolveLabel(v, iBreak); @@ -1892,6 +1958,7 @@ static int multiSelect( *apColl = db->pDfltColl; } } + pKeyInfo->aSortOrder = (u8*)apColl; for(pLoop=p; pLoop; pLoop=pLoop->pPrior){ for(i=0; i<2; i++){ @@ -1965,7 +2032,7 @@ static int generateOutputSubroutine( (char*)pKeyInfo, p4type); sqlite3VdbeAddOp3(v, OP_Jump, j2+2, iContinue, j2+2); sqlite3VdbeJumpHere(v, j1); - sqlite3ExprCodeCopy(pParse, pIn->iSdst, regPrev+1, pIn->nSdst); + sqlite3VdbeAddOp3(v, OP_Copy, pIn->iSdst, regPrev+1, pIn->nSdst-1); sqlite3VdbeAddOp2(v, OP_Integer, 1, regPrev); } if( pParse->db->mallocFailed ) return 0; @@ -2000,10 +2067,10 @@ static int generateOutputSubroutine( case SRT_Set: { int r1; assert( pIn->nSdst==1 ); - p->affinity = + pDest->affSdst = sqlite3CompareAffinity(p->pEList->a[0].pExpr, pDest->affSdst); r1 = sqlite3GetTempReg(pParse); - sqlite3VdbeAddOp4(v, OP_MakeRecord, pIn->iSdst, 1, r1, &p->affinity, 1); + sqlite3VdbeAddOp4(v, OP_MakeRecord, pIn->iSdst, 1, r1, &pDest->affSdst,1); sqlite3ExprCacheAffinityChange(pParse, pIn->iSdst, 1); sqlite3VdbeAddOp2(v, OP_IdxInsert, pDest->iSDParm, r1); sqlite3ReleaseTempReg(pParse, r1); @@ -2269,12 +2336,13 @@ static int multiSelectOrderBy( for(i=0; i<nOrderBy; i++){ CollSeq *pColl; Expr *pTerm = pOrderBy->a[i].pExpr; - if( pTerm->flags & EP_ExpCollate ){ - pColl = pTerm->pColl; + if( pTerm->flags & EP_Collate ){ + pColl = sqlite3ExprCollSeq(pParse, pTerm); }else{ pColl = multiSelectCollSeq(pParse, p, aPermute[i]); - pTerm->flags |= EP_ExpCollate; - pTerm->pColl = pColl; + if( pColl==0 ) pColl = db->pDfltColl; + pOrderBy->a[i].pExpr = + sqlite3ExprAddCollateString(pParse, pTerm, pColl->zName); } pKeyMerge->aColl[i] = pColl; pKeyMerge->aSortOrder[i] = pOrderBy->a[i].sortOrder; @@ -2298,7 +2366,8 @@ static int multiSelectOrderBy( }else{ int nExpr = p->pEList->nExpr; assert( nOrderBy>=nExpr || db->mallocFailed ); - regPrev = sqlite3GetTempRange(pParse, nExpr+1); + regPrev = pParse->nMem+1; + pParse->nMem += nExpr+1; sqlite3VdbeAddOp2(v, OP_Integer, 0, regPrev); pKeyDup = sqlite3DbMallocZero(db, sizeof(*pKeyDup) + nExpr*(sizeof(CollSeq*)+1) ); @@ -2477,14 +2546,9 @@ static int multiSelectOrderBy( sqlite3VdbeAddOp4(v, OP_Permutation, 0, 0, 0, (char*)aPermute, P4_INTARRAY); sqlite3VdbeAddOp4(v, OP_Compare, destA.iSdst, destB.iSdst, nOrderBy, (char*)pKeyMerge, P4_KEYINFO_HANDOFF); + sqlite3VdbeChangeP5(v, OPFLAG_PERMUTE); 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); @@ -2544,9 +2608,6 @@ static Expr *substExpr( 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; } @@ -2745,7 +2806,7 @@ static int flattenSubquery( */ assert( p!=0 ); assert( p->pPrior==0 ); /* Unable to flatten compound queries */ - if( db->flags & SQLITE_QueryFlattener ) return 0; + if( OptimizationDisabled(db, SQLITE_QueryFlattener) ) return 0; pSrc = p->pSrc; assert( pSrc && iFrom>=0 && iFrom<pSrc->nSrc ); pSubitem = &pSrc->a[iFrom]; @@ -2899,12 +2960,15 @@ static int flattenSubquery( Select *pNew; ExprList *pOrderBy = p->pOrderBy; Expr *pLimit = p->pLimit; + Expr *pOffset = p->pOffset; Select *pPrior = p->pPrior; p->pOrderBy = 0; p->pSrc = 0; p->pPrior = 0; p->pLimit = 0; + p->pOffset = 0; pNew = sqlite3SelectDup(db, p, 0); + p->pOffset = pOffset; p->pLimit = pLimit; p->pOrderBy = pOrderBy; p->pSrc = pSrc; @@ -3034,10 +3098,9 @@ static int flattenSubquery( 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); - } + char *zName = sqlite3DbStrDup(db, pList->a[i].zSpan); + sqlite3Dequote(zName); + pList->a[i].zName = zName; } } substExprList(db, pParent->pEList, iParent, pSub->pEList); @@ -3098,34 +3161,43 @@ static int flattenSubquery( #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: +** Based on the contents of the AggInfo structure indicated by the first +** argument, this function checks if the following are true: +** +** * the query contains just a single aggregate function, +** * the aggregate function is either min() or max(), and +** * the argument to the aggregate function is a column value. ** -** 1. There is a single object in the FROM clause. +** If all of the above are true, then WHERE_ORDERBY_MIN or WHERE_ORDERBY_MAX +** is returned as appropriate. Also, *ppMinMax is set to point to the +** list of arguments passed to the aggregate before returning. ** -** 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. +** Or, if the conditions above are not met, *ppMinMax is set to 0 and +** WHERE_ORDERBY_NORMAL is returned. */ -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; +static u8 minMaxQuery(AggInfo *pAggInfo, ExprList **ppMinMax){ + int eRet = WHERE_ORDERBY_NORMAL; /* Return value */ + + *ppMinMax = 0; + if( pAggInfo->nFunc==1 ){ + Expr *pExpr = pAggInfo->aFunc[0].pExpr; /* Aggregate function */ + ExprList *pEList = pExpr->x.pList; /* Arguments to agg function */ + + assert( pExpr->op==TK_AGG_FUNCTION ); + if( pEList && pEList->nExpr==1 && pEList->a[0].pExpr->op==TK_AGG_COLUMN ){ + const char *zFunc = pExpr->u.zToken; + if( sqlite3StrICmp(zFunc, "min")==0 ){ + eRet = WHERE_ORDERBY_MIN; + *ppMinMax = pEList; + }else if( sqlite3StrICmp(zFunc, "max")==0 ){ + eRet = WHERE_ORDERBY_MAX; + *ppMinMax = pEList; + } + } } - return WHERE_ORDERBY_NORMAL; + + assert( *ppMinMax==0 || (*ppMinMax)->nExpr==1 ); + return eRet; } /* @@ -3188,6 +3260,69 @@ int sqlite3IndexedByLookup(Parse *pParse, struct SrcList_item *pFrom){ } return SQLITE_OK; } +/* +** Detect compound SELECT statements that use an ORDER BY clause with +** an alternative collating sequence. +** +** SELECT ... FROM t1 EXCEPT SELECT ... FROM t2 ORDER BY .. COLLATE ... +** +** These are rewritten as a subquery: +** +** SELECT * FROM (SELECT ... FROM t1 EXCEPT SELECT ... FROM t2) +** ORDER BY ... COLLATE ... +** +** This transformation is necessary because the multiSelectOrderBy() routine +** above that generates the code for a compound SELECT with an ORDER BY clause +** uses a merge algorithm that requires the same collating sequence on the +** result columns as on the ORDER BY clause. See ticket +** http://www.sqlite.org/src/info/6709574d2a +** +** This transformation is only needed for EXCEPT, INTERSECT, and UNION. +** The UNION ALL operator works fine with multiSelectOrderBy() even when +** there are COLLATE terms in the ORDER BY. +*/ +static int convertCompoundSelectToSubquery(Walker *pWalker, Select *p){ + int i; + Select *pNew; + Select *pX; + sqlite3 *db; + struct ExprList_item *a; + SrcList *pNewSrc; + Parse *pParse; + Token dummy; + + if( p->pPrior==0 ) return WRC_Continue; + if( p->pOrderBy==0 ) return WRC_Continue; + for(pX=p; pX && (pX->op==TK_ALL || pX->op==TK_SELECT); pX=pX->pPrior){} + if( pX==0 ) return WRC_Continue; + a = p->pOrderBy->a; + for(i=p->pOrderBy->nExpr-1; i>=0; i--){ + if( a[i].pExpr->flags & EP_Collate ) break; + } + if( i<0 ) return WRC_Continue; + + /* If we reach this point, that means the transformation is required. */ + + pParse = pWalker->pParse; + db = pParse->db; + pNew = sqlite3DbMallocZero(db, sizeof(*pNew) ); + if( pNew==0 ) return WRC_Abort; + memset(&dummy, 0, sizeof(dummy)); + pNewSrc = sqlite3SrcListAppendFromTerm(pParse,0,0,0,&dummy,pNew,0,0); + if( pNewSrc==0 ) return WRC_Abort; + *pNew = *p; + p->pSrc = pNewSrc; + p->pEList = sqlite3ExprListAppend(pParse, 0, sqlite3Expr(db, TK_ALL, 0)); + p->op = TK_SELECT; + p->pWhere = 0; + pNew->pGroupBy = 0; + pNew->pHaving = 0; + pNew->pOrderBy = 0; + p->pPrior = 0; + pNew->pLimit = 0; + pNew->pOffset = 0; + return WRC_Continue; +} /* ** This routine is a Walker callback for "expanding" a SELECT statement. @@ -3220,14 +3355,16 @@ static int selectExpander(Walker *pWalker, Select *p){ ExprList *pEList; struct SrcList_item *pFrom; sqlite3 *db = pParse->db; + Expr *pE, *pRight, *pExpr; + u16 selFlags = p->selFlags; + p->selFlags |= SF_Expanded; if( db->mallocFailed ){ return WRC_Abort; } - if( NEVER(p->pSrc==0) || (p->selFlags & SF_Expanded)!=0 ){ + if( NEVER(p->pSrc==0) || (selFlags & SF_Expanded)!=0 ){ return WRC_Prune; } - p->selFlags |= SF_Expanded; pTabList = p->pSrc; pEList = p->pEList; @@ -3268,9 +3405,14 @@ static int selectExpander(Walker *pWalker, Select *p){ }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); + pFrom->pTab = pTab = sqlite3LocateTableItem(pParse, 0, pFrom); if( pTab==0 ) return WRC_Abort; + if( pTab->nRef==0xffff ){ + sqlite3ErrorMsg(pParse, "too many references to \"%s\": max 65535", + pTab->zName); + pFrom->pTab = 0; + return WRC_Abort; + } pTab->nRef++; #if !defined(SQLITE_OMIT_VIEW) || !defined (SQLITE_OMIT_VIRTUALTABLE) if( pTab->pSelect || IsVirtual(pTab) ){ @@ -3306,7 +3448,7 @@ static int selectExpander(Walker *pWalker, Select *p){ ** that need expanding. */ for(k=0; k<pEList->nExpr; k++){ - Expr *pE = pEList->a[k].pExpr; + 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) ); @@ -3324,10 +3466,18 @@ static int selectExpander(Walker *pWalker, Select *p){ int longNames = (flags & SQLITE_FullColNames)!=0 && (flags & SQLITE_ShortColNames)==0; + /* When processing FROM-clause subqueries, it is always the case + ** that full_column_names=OFF and short_column_names=ON. The + ** sqlite3ResultSetOfSelect() routine makes it so. */ + assert( (p->selFlags & SF_NestedFrom)==0 + || ((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) ){ + pE = a[k].pExpr; + pRight = pE->pRight; + assert( pE->op!=TK_DOT || pRight!=0 ); + if( pE->op!=TK_ALL && (pE->op!=TK_DOT || pRight->op!=TK_ALL) ){ /* This particular expression does not need to be expanded. */ pNew = sqlite3ExprListAppend(pParse, pNew, a[k].pExpr); @@ -3342,32 +3492,43 @@ static int selectExpander(Walker *pWalker, Select *p){ /* 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 */ + char *zTName = 0; /* 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; + Select *pSub = pFrom->pSelect; char *zTabName = pFrom->zAlias; + const char *zSchemaName = 0; + int iDb; if( zTabName==0 ){ zTabName = pTab->zName; } if( db->mallocFailed ) break; - if( zTName && sqlite3StrICmp(zTName, zTabName)!=0 ){ - continue; + if( pSub==0 || (pSub->selFlags & SF_NestedFrom)==0 ){ + pSub = 0; + if( zTName && sqlite3StrICmp(zTName, zTabName)!=0 ){ + continue; + } + iDb = sqlite3SchemaToIndex(db, pTab->pSchema); + zSchemaName = iDb>=0 ? db->aDb[iDb].zName : "*"; } - 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 */ + assert( zName ); + if( zTName && pSub + && sqlite3MatchSpanName(pSub->pEList->a[j].zSpan, 0, zTName, 0)==0 + ){ + continue; + } + /* If a column is marked as 'hidden' (currently only possible ** for virtual tables), do not include it in the expanded ** result-set list. @@ -3376,6 +3537,7 @@ static int selectExpander(Walker *pWalker, Select *p){ assert(IsVirtual(pTab)); continue; } + tableSeen = 1; if( i>0 && zTName==0 ){ if( (pFrom->jointype & JT_NATURAL)!=0 @@ -3398,6 +3560,10 @@ static int selectExpander(Walker *pWalker, Select *p){ Expr *pLeft; pLeft = sqlite3Expr(db, TK_ID, zTabName); pExpr = sqlite3PExpr(pParse, TK_DOT, pLeft, pRight, 0); + if( zSchemaName ){ + pLeft = sqlite3Expr(db, TK_ID, zSchemaName); + pExpr = sqlite3PExpr(pParse, TK_DOT, pLeft, pExpr, 0); + } if( longNames ){ zColname = sqlite3MPrintf(db, "%s.%s", zTabName, zName); zToFree = zColname; @@ -3409,6 +3575,18 @@ static int selectExpander(Walker *pWalker, Select *p){ sColname.z = zColname; sColname.n = sqlite3Strlen30(zColname); sqlite3ExprListSetName(pParse, pNew, &sColname, 0); + if( pNew && (p->selFlags & SF_NestedFrom)!=0 ){ + struct ExprList_item *pX = &pNew->a[pNew->nExpr-1]; + if( pSub ){ + pX->zSpan = sqlite3DbStrDup(db, pSub->pEList->a[j].zSpan); + testcase( pX->zSpan==0 ); + }else{ + pX->zSpan = sqlite3MPrintf(db, "%s.%s.%s", + zSchemaName, zTabName, zColname); + testcase( pX->zSpan==0 ); + } + pX->bSpanIsTab = 1; + } sqlite3DbFree(db, zToFree); } } @@ -3461,10 +3639,13 @@ static int exprWalkNoop(Walker *NotUsed, Expr *NotUsed2){ */ static void sqlite3SelectExpand(Parse *pParse, Select *pSelect){ Walker w; - w.xSelectCallback = selectExpander; + memset(&w, 0, sizeof(w)); + w.xSelectCallback = convertCompoundSelectToSubquery; w.xExprCallback = exprWalkNoop; w.pParse = pParse; sqlite3WalkSelect(&w, pSelect); + w.xSelectCallback = selectExpander; + sqlite3WalkSelect(&w, pSelect); } @@ -3519,9 +3700,11 @@ static int selectAddSubqueryTypeInfo(Walker *pWalker, Select *p){ static void sqlite3SelectAddTypeInfo(Parse *pParse, Select *pSelect){ #ifndef SQLITE_OMIT_SUBQUERY Walker w; + memset(&w, 0, sizeof(w)); w.xSelectCallback = selectAddSubqueryTypeInfo; w.xExprCallback = exprWalkNoop; w.pParse = pParse; + w.bSelectDepthFirst = 1; sqlite3WalkSelect(&w, pSelect); #endif } @@ -3547,6 +3730,7 @@ void sqlite3SelectPrep( sqlite3 *db; if( NEVER(p==0) ) return; db = pParse->db; + if( db->mallocFailed ) return; if( p->selFlags & SF_HasTypeInfo ) return; sqlite3SelectExpand(pParse, p); if( pParse->nErr || db->mallocFailed ) return; @@ -3785,11 +3969,9 @@ int sqlite3Select( 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 */ - int addrDistinctIndex; /* Address of an OP_OpenEphemeral instruction */ + DistinctCtx sDistinct; /* Info on how to code the DISTINCT keyword */ AggInfo sAggInfo; /* Information used by aggregate queries */ int iEnd; /* Address of the end of the query */ sqlite3 *db; /* The database connection */ @@ -3849,8 +4031,17 @@ int sqlite3Select( int isAggSub; if( pSub==0 ) continue; + + /* Sometimes the code for a subquery will be generated more than + ** once, if the subquery is part of the WHERE clause in a LEFT JOIN, + ** for example. In that case, do not regenerate the code to manifest + ** a view or the co-routine to implement a view. The first instance + ** is sufficient, though the subroutine to manifest the view does need + ** to be invoked again. */ if( pItem->addrFillSub ){ - sqlite3VdbeAddOp2(v, OP_Gosub, pItem->regReturn, pItem->addrFillSub); + if( pItem->viaCoroutine==0 ){ + sqlite3VdbeAddOp2(v, OP_Gosub, pItem->regReturn, pItem->addrFillSub); + } continue; } @@ -3871,6 +4062,44 @@ int sqlite3Select( p->selFlags |= SF_Aggregate; } i = -1; + }else if( pTabList->nSrc==1 && (p->selFlags & SF_Materialize)==0 + && OptimizationEnabled(db, SQLITE_SubqCoroutine) + ){ + /* Implement a co-routine that will return a single row of the result + ** set on each invocation. + */ + int addrTop; + int addrEof; + pItem->regReturn = ++pParse->nMem; + addrEof = ++pParse->nMem; + /* Before coding the OP_Goto to jump to the start of the main routine, + ** ensure that the jump to the verify-schema routine has already + ** been coded. Otherwise, the verify-schema would likely be coded as + ** part of the co-routine. If the main routine then accessed the + ** database before invoking the co-routine for the first time (for + ** example to initialize a LIMIT register from a sub-select), it would + ** be doing so without having verified the schema version and obtained + ** the required db locks. See ticket d6b36be38. */ + sqlite3CodeVerifySchema(pParse, -1); + sqlite3VdbeAddOp0(v, OP_Goto); + addrTop = sqlite3VdbeAddOp1(v, OP_OpenPseudo, pItem->iCursor); + sqlite3VdbeChangeP5(v, 1); + VdbeComment((v, "coroutine for %s", pItem->pTab->zName)); + pItem->addrFillSub = addrTop; + sqlite3VdbeAddOp2(v, OP_Integer, 0, addrEof); + sqlite3VdbeChangeP5(v, 1); + sqlite3SelectDestInit(&dest, SRT_Coroutine, pItem->regReturn); + explainSetInteger(pItem->iSelectId, (u8)pParse->iNextSelectId); + sqlite3Select(pParse, pSub, &dest); + pItem->pTab->nRowEst = (unsigned)pSub->nSelectRow; + pItem->viaCoroutine = 1; + sqlite3VdbeChangeP2(v, addrTop, dest.iSdst); + sqlite3VdbeChangeP3(v, addrTop, dest.nSdst); + sqlite3VdbeAddOp2(v, OP_Integer, 1, addrEof); + sqlite3VdbeAddOp1(v, OP_Yield, pItem->regReturn); + VdbeComment((v, "end %s", pItem->pTab->zName)); + sqlite3VdbeJumpHere(v, addrTop-1); + sqlite3ClearTempRegCache(pParse); }else{ /* Generate a subroutine that will fill an ephemeral table with ** the content of this subquery. pItem->addrFillSub will point @@ -3886,7 +4115,7 @@ int sqlite3Select( pItem->addrFillSub = topAddr+1; VdbeNoopComment((v, "materialize %s", pItem->pTab->zName)); if( pItem->isCorrelated==0 ){ - /* If the subquery is no correlated and if we are not inside of + /* If the subquery is not correlated and if we are not inside of ** a trigger, then we only need to compute the value of the subquery ** once. */ onceAddr = sqlite3CodeOnce(pParse); @@ -3915,7 +4144,7 @@ int sqlite3Select( pWhere = p->pWhere; pGroupBy = p->pGroupBy; pHaving = p->pHaving; - isDistinct = (p->selFlags & SF_Distinct)!=0; + sDistinct.isTnct = (p->selFlags & SF_Distinct)!=0; #ifndef SQLITE_OMIT_COMPOUND_SELECT /* If there is are a sequence of queries, do the earlier ones first. @@ -3950,7 +4179,7 @@ int sqlite3Select( ** to disable this optimization for testing purposes. */ if( sqlite3ExprListCompare(p->pGroupBy, pOrderBy)==0 - && (db->flags & SQLITE_GroupByOrder)==0 ){ + && OptimizationEnabled(db, SQLITE_GroupByOrder) ){ pOrderBy = 0; } @@ -3976,6 +4205,10 @@ int sqlite3Select( p->pGroupBy = sqlite3ExprListDup(db, p->pEList, 0); pGroupBy = p->pGroupBy; pOrderBy = 0; + /* Notice that even thought SF_Distinct has been cleared from p->selFlags, + ** the sDistinct.isTnct is still set. Hence, isTnct represents the + ** original setting of the SF_Distinct flag, not the current setting */ + assert( sDistinct.isTnct ); } /* If there is an ORDER BY clause, then this sorting @@ -4016,24 +4249,27 @@ int sqlite3Select( /* Open a virtual index to use for the distinct set. */ if( p->selFlags & SF_Distinct ){ - KeyInfo *pKeyInfo; - distinct = pParse->nTab++; - pKeyInfo = keyInfoFromExprList(pParse, p->pEList); - addrDistinctIndex = sqlite3VdbeAddOp4(v, OP_OpenEphemeral, distinct, 0, 0, - (char*)pKeyInfo, P4_KEYINFO_HANDOFF); + sDistinct.tabTnct = pParse->nTab++; + sDistinct.addrTnct = sqlite3VdbeAddOp4(v, OP_OpenEphemeral, + sDistinct.tabTnct, 0, 0, + (char*)keyInfoFromExprList(pParse, p->pEList), + P4_KEYINFO_HANDOFF); sqlite3VdbeChangeP5(v, BTREE_UNORDERED); + sDistinct.eTnctType = WHERE_DISTINCT_UNORDERED; }else{ - distinct = addrDistinctIndex = -1; + sDistinct.eTnctType = WHERE_DISTINCT_NOOP; } - /* Aggregate and non-aggregate queries are handled differently */ if( !isAgg && pGroupBy==0 ){ - ExprList *pDist = (isDistinct ? p->pEList : 0); + /* No aggregate functions and no GROUP BY clause */ + ExprList *pDist = (sDistinct.isTnct ? p->pEList : 0); /* Begin the database scan. */ - pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, &pOrderBy, pDist, 0,0); + pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, pOrderBy, pDist, 0,0); if( pWInfo==0 ) goto select_end; if( pWInfo->nRowOut < p->nSelectRow ) p->nSelectRow = pWInfo->nRowOut; + if( pWInfo->eDistinct ) sDistinct.eTnctType = pWInfo->eDistinct; + if( pOrderBy && pWInfo->nOBSat==pOrderBy->nExpr ) pOrderBy = 0; /* If sorting index that was created by a prior OP_OpenEphemeral ** instruction ended up not being needed, then change the OP_OpenEphemeral @@ -4044,59 +4280,16 @@ int sqlite3Select( p->addrOpenEphm[2] = -1; } - if( pWInfo->eDistinct ){ - VdbeOp *pOp; /* No longer required OpenEphemeral instr. */ - - assert( addrDistinctIndex>=0 ); - pOp = sqlite3VdbeGetOp(v, addrDistinctIndex); - - assert( isDistinct ); - assert( pWInfo->eDistinct==WHERE_DISTINCT_ORDERED - || pWInfo->eDistinct==WHERE_DISTINCT_UNIQUE - ); - distinct = -1; - if( pWInfo->eDistinct==WHERE_DISTINCT_ORDERED ){ - int iJump; - int iExpr; - int iFlag = ++pParse->nMem; - int iBase = pParse->nMem+1; - int iBase2 = iBase + pEList->nExpr; - pParse->nMem += (pEList->nExpr*2); - - /* Change the OP_OpenEphemeral coded earlier to an OP_Integer. The - ** OP_Integer initializes the "first row" flag. */ - pOp->opcode = OP_Integer; - pOp->p1 = 1; - pOp->p2 = iFlag; - - sqlite3ExprCodeExprList(pParse, pEList, iBase, 1); - iJump = sqlite3VdbeCurrentAddr(v) + 1 + pEList->nExpr + 1 + 1; - sqlite3VdbeAddOp2(v, OP_If, iFlag, iJump-1); - for(iExpr=0; iExpr<pEList->nExpr; iExpr++){ - CollSeq *pColl = sqlite3ExprCollSeq(pParse, pEList->a[iExpr].pExpr); - sqlite3VdbeAddOp3(v, OP_Ne, iBase+iExpr, iJump, iBase2+iExpr); - sqlite3VdbeChangeP4(v, -1, (const char *)pColl, P4_COLLSEQ); - sqlite3VdbeChangeP5(v, SQLITE_NULLEQ); - } - sqlite3VdbeAddOp2(v, OP_Goto, 0, pWInfo->iContinue); - - sqlite3VdbeAddOp2(v, OP_Integer, 0, iFlag); - assert( sqlite3VdbeCurrentAddr(v)==iJump ); - sqlite3VdbeAddOp3(v, OP_Move, iBase, iBase2, pEList->nExpr); - }else{ - pOp->opcode = OP_Noop; - } - } - /* Use the standard inner loop. */ - selectInnerLoop(pParse, p, pEList, 0, 0, pOrderBy, distinct, pDest, + selectInnerLoop(pParse, p, pEList, 0, 0, pOrderBy, &sDistinct, pDest, pWInfo->iContinue, pWInfo->iBreak); /* End the database scan loop. */ sqlite3WhereEnd(pWInfo); }else{ - /* This is the processing for aggregate queries */ + /* This case when there exist aggregate functions or a GROUP BY clause + ** or both */ 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 */ @@ -4204,14 +4397,13 @@ int sqlite3Select( ** in the right order to begin with. */ sqlite3VdbeAddOp2(v, OP_Gosub, regReset, addrReset); - pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, &pGroupBy, 0, 0, 0); + pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, pGroupBy, 0, 0, 0); if( pWInfo==0 ) goto select_end; - if( pGroupBy==0 ){ + if( pWInfo->nOBSat==pGroupBy->nExpr ){ /* 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 @@ -4225,7 +4417,8 @@ int sqlite3Select( int nGroupBy; explainTempTable(pParse, - isDistinct && !(p->selFlags&SF_Distinct)?"DISTINCT":"GROUP BY"); + (sDistinct.isTnct && (p->selFlags&SF_Distinct)==0) ? + "DISTINCT" : "GROUP BY"); groupBySort = 1; nGroupBy = pGroupBy->nExpr; @@ -4357,7 +4550,7 @@ int sqlite3Select( finalizeAggFunctions(pParse, &sAggInfo); sqlite3ExprIfFalse(pParse, pHaving, addrOutputRow+1, SQLITE_JUMPIFNULL); selectInnerLoop(pParse, p, p->pEList, 0, 0, pOrderBy, - distinct, pDest, + &sDistinct, pDest, addrOutputRow+1, addrSetAbort); sqlite3VdbeAddOp1(v, OP_Return, regOutputRow); VdbeComment((v, "end groupby result generator")); @@ -4445,7 +4638,7 @@ int sqlite3Select( ** value of x, the only row required). ** ** A special flag must be passed to sqlite3WhereBegin() to slightly - ** modify behaviour as follows: + ** modify behavior 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 @@ -4457,10 +4650,17 @@ int sqlite3Select( ** Refer to code and comments in where.c for details. */ ExprList *pMinMax = 0; - u8 flag = minMaxQuery(p); + u8 flag = WHERE_ORDERBY_NORMAL; + + assert( p->pGroupBy==0 ); + assert( flag==0 ); + if( p->pHaving==0 ){ + flag = minMaxQuery(&sAggInfo, &pMinMax); + } + assert( flag==0 || (pMinMax!=0 && pMinMax->nExpr==1) ); + if( flag ){ - assert( !ExprHasProperty(p->pEList->a[0].pExpr, EP_xIsSelect) ); - pMinMax = sqlite3ExprListDup(db, p->pEList->a[0].pExpr->x.pList,0); + pMinMax = sqlite3ExprListDup(db, pMinMax, 0); pDel = pMinMax; if( pMinMax && !db->mallocFailed ){ pMinMax->a[0].sortOrder = flag!=WHERE_ORDERBY_MIN ?1:0; @@ -4473,13 +4673,14 @@ int sqlite3Select( ** of output. */ resetAccumulator(pParse, &sAggInfo); - pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, &pMinMax,0,flag,0); + pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, pMinMax,0,flag,0); if( pWInfo==0 ){ sqlite3ExprListDelete(db, pDel); goto select_end; } updateAccumulator(pParse, &sAggInfo); - if( !pMinMax && flag ){ + assert( pMinMax==0 || pMinMax->nExpr==1 ); + if( pWInfo->nOBSat>0 ){ sqlite3VdbeAddOp2(v, OP_Goto, 0, pWInfo->iBreak); VdbeComment((v, "%s() by index", (flag==WHERE_ORDERBY_MIN?"min":"max"))); @@ -4490,7 +4691,7 @@ int sqlite3Select( pOrderBy = 0; sqlite3ExprIfFalse(pParse, pHaving, addrEnd, SQLITE_JUMPIFNULL); - selectInnerLoop(pParse, p, p->pEList, 0, 0, 0, -1, + selectInnerLoop(pParse, p, p->pEList, 0, 0, 0, 0, pDest, addrEnd, addrEnd); sqlite3ExprListDelete(db, pDel); } @@ -4498,7 +4699,7 @@ int sqlite3Select( } /* endif aggregate query */ - if( distinct>=0 ){ + if( sDistinct.eTnctType==WHERE_DISTINCT_UNORDERED ){ explainTempTable(pParse, "DISTINCT"); } @@ -4615,7 +4816,10 @@ void sqlite3ExplainSelect(Vdbe *pVdbe, Select *p){ sqlite3ExplainPrintf(pVdbe, "(null-select)"); return; } - while( p->pPrior ) p = p->pPrior; + while( p->pPrior ){ + p->pPrior->pNext = p; + p = p->pPrior; + } sqlite3ExplainPush(pVdbe); while( p ){ explainOneSelect(pVdbe, p); |