diff options
Diffstat (limited to 'src/select.c')
| -rw-r--r-- | src/select.c | 169 |
1 files changed, 148 insertions, 21 deletions
diff --git a/src/select.c b/src/select.c index 3b951afff..1b1266313 100644 --- a/src/select.c +++ b/src/select.c @@ -384,7 +384,7 @@ static int tableAndColumnIndex( int iEnd, /* Last member of pSrc->a[] to check */ 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 *piCol, /* Write index of pSrc->a[*piTab].pSTab->aCol[] here */ int bIgnoreHidden /* Ignore hidden columns */ ){ int i; /* For looping over tables in pSrc */ @@ -596,7 +596,7 @@ static int sqlite3ProcessJoin(Parse *pParse, Select *p){ } pE1 = sqlite3CreateColumnExpr(db, pSrc, iLeft, iLeftCol); sqlite3SrcItemColumnUsed(&pSrc->a[iLeft], iLeftCol); - if( (pSrc->a[0].fg.jointype & JT_LTORJ)!=0 ){ + if( (pSrc->a[0].fg.jointype & JT_LTORJ)!=0 && pParse->nErr==0 ){ /* This branch runs if the query contains one or more RIGHT or FULL ** JOINs. If only a single table on the left side of this join ** contains the zName column, then this branch is a no-op. @@ -612,6 +612,8 @@ static int sqlite3ProcessJoin(Parse *pParse, Select *p){ */ ExprList *pFuncArgs = 0; /* Arguments to the coalesce() */ static const Token tkCoalesce = { "coalesce", 8 }; + assert( pE1!=0 ); + ExprSetProperty(pE1, EP_CanBeNull); while( tableAndColumnIndex(pSrc, iLeft+1, i, zName, &iLeft, &iLeftCol, pRight->fg.isSynthUsing)!=0 ){ if( pSrc->a[iLeft].fg.isUsing==0 @@ -628,7 +630,13 @@ static int sqlite3ProcessJoin(Parse *pParse, Select *p){ if( pFuncArgs ){ pFuncArgs = sqlite3ExprListAppend(pParse, pFuncArgs, pE1); pE1 = sqlite3ExprFunction(pParse, pFuncArgs, &tkCoalesce, 0); + if( pE1 ){ + pE1->affExpr = SQLITE_AFF_DEFER; + } } + }else if( (pSrc->a[i+1].fg.jointype & JT_LEFT)!=0 && pParse->nErr==0 ){ + assert( pE1!=0 ); + ExprSetProperty(pE1, EP_CanBeNull); } pE2 = sqlite3CreateColumnExpr(db, pSrc, i+1, iRightCol); sqlite3SrcItemColumnUsed(pRight, iRightCol); @@ -2105,6 +2113,10 @@ static void generateColumnTypes( #endif sqlite3VdbeSetColName(v, i, COLNAME_DECLTYPE, zType, SQLITE_TRANSIENT); } +#else + UNUSED_PARAMETER(pParse); + UNUSED_PARAMETER(pTabList); + UNUSED_PARAMETER(pEList); #endif /* !defined(SQLITE_OMIT_DECLTYPE) */ } @@ -3024,7 +3036,9 @@ static int multiSelect( int priorOp; /* The SRT_ operation to apply to prior selects */ Expr *pLimit; /* Saved values of p->nLimit */ int addr; + int emptyBypass = 0; /* IfEmpty opcode to bypass RHS */ SelectDest uniondest; + testcase( p->op==TK_EXCEPT ); testcase( p->op==TK_UNION ); @@ -3063,6 +3077,8 @@ static int multiSelect( */ if( p->op==TK_EXCEPT ){ op = SRT_Except; + emptyBypass = sqlite3VdbeAddOp1(v, OP_IfEmpty, unionTab); + VdbeCoverage(v); }else{ assert( p->op==TK_UNION ); op = SRT_Union; @@ -3083,6 +3099,7 @@ static int multiSelect( if( p->op==TK_UNION ){ p->nSelectRow = sqlite3LogEstAdd(p->nSelectRow, pPrior->nSelectRow); } + if( emptyBypass ) sqlite3VdbeJumpHere(v, emptyBypass); sqlite3ExprDelete(db, p->pLimit); p->pLimit = pLimit; p->iLimit = 0; @@ -3113,9 +3130,10 @@ static int multiSelect( int tab1, tab2; int iCont, iBreak, iStart; Expr *pLimit; - int addr; + int addr, iLimit, iOffset; SelectDest intersectdest; int r1; + int emptyBypass; /* INTERSECT is different from the others since it requires ** two temporary tables. Hence it has its own case. Begin @@ -3139,15 +3157,29 @@ static int multiSelect( if( rc ){ goto multi_select_end; } + + /* Initialize LIMIT counters before checking to see if the LHS + ** is empty, in case the jump is taken */ + iBreak = sqlite3VdbeMakeLabel(pParse); + computeLimitRegisters(pParse, p, iBreak); + emptyBypass = sqlite3VdbeAddOp1(v, OP_IfEmpty, tab1); VdbeCoverage(v); /* 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; + + /* Disable prior SELECTs and the LIMIT counters during the computation + ** of the RHS select */ pLimit = p->pLimit; + iLimit = p->iLimit; + iOffset = p->iOffset; + p->pPrior = 0; p->pLimit = 0; + p->iLimit = 0; + p->iOffset = 0; + intersectdest.iSDParm = tab2; ExplainQueryPlan((pParse, 1, "%s USING TEMP B-TREE", sqlite3SelectOpName(p->op))); @@ -3160,19 +3192,21 @@ static int multiSelect( p->nSelectRow = pPrior->nSelectRow; } sqlite3ExprDelete(db, p->pLimit); + + /* Reinstate the LIMIT counters prior to running the final intersect */ p->pLimit = pLimit; + p->iLimit = iLimit; + p->iOffset = iOffset; /* Generate code to take the intersection of the two temporary ** tables. */ if( rc ) break; assert( p->pEList ); - iBreak = sqlite3VdbeMakeLabel(pParse); - iCont = sqlite3VdbeMakeLabel(pParse); - computeLimitRegisters(pParse, p, iBreak); - sqlite3VdbeAddOp2(v, OP_Rewind, tab1, iBreak); VdbeCoverage(v); + sqlite3VdbeAddOp1(v, OP_Rewind, tab1); r1 = sqlite3GetTempReg(pParse); iStart = sqlite3VdbeAddOp2(v, OP_RowData, tab1, r1); + iCont = sqlite3VdbeMakeLabel(pParse); sqlite3VdbeAddOp4Int(v, OP_NotFound, tab2, iCont, r1, 0); VdbeCoverage(v); sqlite3ReleaseTempReg(pParse, r1); @@ -3182,6 +3216,7 @@ static int multiSelect( sqlite3VdbeAddOp2(v, OP_Next, tab1, iStart); VdbeCoverage(v); sqlite3VdbeResolveLabel(v, iBreak); sqlite3VdbeAddOp2(v, OP_Close, tab2, 0); + sqlite3VdbeJumpHere(v, emptyBypass); sqlite3VdbeAddOp2(v, OP_Close, tab1, 0); break; } @@ -3860,6 +3895,7 @@ typedef struct SubstContext { int iTable; /* Replace references to this table */ int iNewTable; /* New table number */ int isOuterJoin; /* Add TK_IF_NULL_ROW opcodes on each replacement */ + int nSelDepth; /* Depth of sub-query recursion. Top==1 */ ExprList *pEList; /* Replacement expressions */ ExprList *pCList; /* Collation sequences for replacement expr */ } SubstContext; @@ -3967,6 +4003,9 @@ static Expr *substExpr( if( pExpr->op==TK_IF_NULL_ROW && pExpr->iTable==pSubst->iTable ){ pExpr->iTable = pSubst->iNewTable; } + if( pExpr->op==TK_AGG_FUNCTION && pExpr->op2>=pSubst->nSelDepth ){ + pExpr->op2--; + } pExpr->pLeft = substExpr(pSubst, pExpr->pLeft); pExpr->pRight = substExpr(pSubst, pExpr->pRight); if( ExprUseXSelect(pExpr) ){ @@ -4004,6 +4043,7 @@ static void substSelect( SrcItem *pItem; int i; if( !p ) return; + pSubst->nSelDepth++; do{ substExprList(pSubst, p->pEList); substExprList(pSubst, p->pGroupBy); @@ -4021,6 +4061,7 @@ static void substSelect( } } }while( doPrior && (p = p->pPrior)!=0 ); + pSubst->nSelDepth--; } #endif /* !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) */ @@ -4236,9 +4277,9 @@ static int compoundHasDifferentAffinities(Select *p){ ** from 2015-02-09.) ** ** (3) If the subquery is the right operand of a LEFT JOIN then -** (3a) the subquery may not be a join and -** (3b) the FROM clause of the subquery may not contain a virtual -** table and +** (3a) the subquery may not be a join +** (**) Was (3b): "the FROM clause of the subquery may not contain +** a virtual table" ** (**) Was: "The outer query may not have a GROUP BY." This case ** is now managed correctly ** (3d) the outer query may not be DISTINCT. @@ -4454,7 +4495,7 @@ static int flattenSubquery( */ if( (pSubitem->fg.jointype & (JT_OUTER|JT_LTORJ))!=0 ){ if( pSubSrc->nSrc>1 /* (3a) */ - || IsVirtual(pSubSrc->a[0].pSTab) /* (3b) */ + /**** || IsVirtual(pSubSrc->a[0].pSTab) (3b)-omitted */ || (p->selFlags & SF_Distinct)!=0 /* (3d) */ || (pSubitem->fg.jointype & JT_RIGHT)!=0 /* (26) */ ){ @@ -4632,7 +4673,7 @@ static int flattenSubquery( ** 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. + ** pSubitem->pSTab is always non-NULL by test restrictions and tests above. */ if( ALWAYS(pSubitem->pSTab!=0) ){ Table *pTabToDel = pSubitem->pSTab; @@ -4762,6 +4803,7 @@ static int flattenSubquery( x.iTable = iParent; x.iNewTable = iNewParent; x.isOuterJoin = isOuterJoin; + x.nSelDepth = 0; x.pEList = pSub->pEList; x.pCList = findLeftmostExprlist(pSub); substSelect(&x, pParent, 0); @@ -5347,6 +5389,7 @@ static int pushDownWhereTerms( x.iTable = pSrc->iCursor; x.iNewTable = pSrc->iCursor; x.isOuterJoin = 0; + x.nSelDepth = 0; x.pEList = pSubq->pEList; x.pCList = findLeftmostExprlist(pSubq); pNew = substExpr(&x, pNew); @@ -5744,7 +5787,7 @@ With *sqlite3WithPush(Parse *pParse, With *pWith, u8 bFree){ ** CTE expression, through routine checks to see if the reference is ** a recursive reference to the CTE. ** -** If pFrom matches a CTE according to either of these two above, pFrom->pTab +** If pFrom matches a CTE according to either of these two above, pFrom->pSTab ** and other fields are populated accordingly. ** ** Return 0 if no match is found. @@ -7372,6 +7415,83 @@ static int fromClauseTermCanBeCoroutine( } /* +** Argument pWhere is the WHERE clause belonging to SELECT statement p. This +** function attempts to transform expressions of the form: +** +** EXISTS (SELECT ...) +** +** into joins. For example, given +** +** CREATE TABLE sailors(sid INTEGER PRIMARY KEY, name TEXT); +** CREATE TABLE reserves(sid INT, day DATE, PRIMARY KEY(sid, day)); +** +** SELECT name FROM sailors AS S WHERE EXISTS ( +** SELECT * FROM reserves AS R WHERE S.sid = R.sid AND R.day = '2022-10-25' +** ); +** +** the SELECT statement may be transformed as follows: +** +** SELECT name FROM sailors AS S, reserves AS R +** WHERE S.sid = R.sid AND R.day = '2022-10-25'; +** +** **Approximately**. Really, we have to ensure that the FROM-clause term +** that was formerly inside the EXISTS is only executed once. This is handled +** by setting the SrcItem.fg.fromExists flag, which then causes code in +** the where.c file to exit the corresponding loop after the first successful +** match (if any). +*/ +static SQLITE_NOINLINE void existsToJoin( + Parse *pParse, /* Parsing context */ + Select *p, /* The SELECT statement being optimized */ + Expr *pWhere /* part of the WHERE clause currently being examined */ +){ + if( pParse->nErr==0 + && pWhere!=0 + && !ExprHasProperty(pWhere, EP_OuterON|EP_InnerON) + && ALWAYS(p->pSrc!=0) + && p->pSrc->nSrc<BMS + ){ + if( pWhere->op==TK_AND ){ + Expr *pRight = pWhere->pRight; + existsToJoin(pParse, p, pWhere->pLeft); + existsToJoin(pParse, p, pRight); + } + else if( pWhere->op==TK_EXISTS ){ + Select *pSub = pWhere->x.pSelect; + Expr *pSubWhere = pSub->pWhere; + if( pSub->pSrc->nSrc==1 + && (pSub->selFlags & SF_Aggregate)==0 + && !pSub->pSrc->a[0].fg.isSubquery + ){ + memset(pWhere, 0, sizeof(*pWhere)); + pWhere->op = TK_INTEGER; + pWhere->u.iValue = 1; + ExprSetProperty(pWhere, EP_IntValue); + + assert( p->pWhere!=0 ); + pSub->pSrc->a[0].fg.fromExists = 1; + pSub->pSrc->a[0].fg.jointype |= JT_CROSS; + p->pSrc = sqlite3SrcListAppendList(pParse, p->pSrc, pSub->pSrc); + if( pSubWhere ){ + p->pWhere = sqlite3PExpr(pParse, TK_AND, p->pWhere, pSubWhere); + pSub->pWhere = 0; + } + pSub->pSrc = 0; + sqlite3ParserAddCleanup(pParse, sqlite3SelectDeleteGeneric, pSub); +#if TREETRACE_ENABLED + if( sqlite3TreeTrace & 0x100000 ){ + TREETRACE(0x100000,pParse,p, + ("After EXISTS-to-JOIN optimization:\n")); + sqlite3TreeViewSelect(0, p, 0); + } +#endif + existsToJoin(pParse, p, pSubWhere); + } + } + } +} + +/* ** Generate byte-code for the SELECT statement given in the p argument. ** ** The results are returned according to the SelectDest structure. @@ -7739,6 +7859,13 @@ int sqlite3Select( } #endif + /* If there may be an "EXISTS (SELECT ...)" in the WHERE clause, attempt + ** to change it into a join. */ + if( pParse->bHasExists && OptimizationEnabled(db,SQLITE_ExistsToJoin) ){ + existsToJoin(pParse, p, p->pWhere); + pTabList = p->pSrc; + } + /* Do the WHERE-clause constant propagation optimization if this is ** a join. No need to spend time on this operation for non-join queries ** as the equivalent optimization will be handled by query planner in @@ -8525,12 +8652,12 @@ int sqlite3Select( ** for the next GROUP BY batch. */ sqlite3VdbeAddOp2(v, OP_Gosub, regOutputRow, addrOutputRow); - VdbeComment((v, "output one row")); + VdbeComment((v, "output one row of %d", p->selId)); sqlite3ExprCodeMove(pParse, iBMem, iAMem, pGroupBy->nExpr); sqlite3VdbeAddOp2(v, OP_IfPos, iAbortFlag, addrEnd); VdbeCoverage(v); VdbeComment((v, "check abort flag")); sqlite3VdbeAddOp2(v, OP_Gosub, regReset, addrReset); - VdbeComment((v, "reset accumulator")); + VdbeComment((v, "reset accumulator %d", p->selId)); /* Update the aggregate accumulators based on the content of ** the current row @@ -8538,7 +8665,7 @@ int sqlite3Select( sqlite3VdbeJumpHere(v, addr1); updateAccumulator(pParse, iUseFlag, pAggInfo, eDist); sqlite3VdbeAddOp2(v, OP_Integer, 1, iUseFlag); - VdbeComment((v, "indicate data in accumulator")); + VdbeComment((v, "indicate data in accumulator %d", p->selId)); /* End of the loop */ @@ -8555,7 +8682,7 @@ int sqlite3Select( /* Output the final row of result */ sqlite3VdbeAddOp2(v, OP_Gosub, regOutputRow, addrOutputRow); - VdbeComment((v, "output final row")); + VdbeComment((v, "output final row of %d", p->selId)); /* Jump over the subroutines */ @@ -8576,7 +8703,7 @@ int sqlite3Select( addrOutputRow = sqlite3VdbeCurrentAddr(v); sqlite3VdbeAddOp2(v, OP_IfPos, iUseFlag, addrOutputRow+2); VdbeCoverage(v); - VdbeComment((v, "Groupby result generator entry point")); + VdbeComment((v, "Groupby result generator entry point %d", p->selId)); sqlite3VdbeAddOp1(v, OP_Return, regOutputRow); finalizeAggFunctions(pParse, pAggInfo); sqlite3ExprIfFalse(pParse, pHaving, addrOutputRow+1, SQLITE_JUMPIFNULL); @@ -8584,14 +8711,14 @@ int sqlite3Select( &sDistinct, pDest, addrOutputRow+1, addrSetAbort); sqlite3VdbeAddOp1(v, OP_Return, regOutputRow); - VdbeComment((v, "end groupby result generator")); + VdbeComment((v, "end groupby result generator %d", p->selId)); /* Generate a subroutine that will reset the group-by accumulator */ sqlite3VdbeResolveLabel(v, addrReset); resetAccumulator(pParse, pAggInfo); sqlite3VdbeAddOp2(v, OP_Integer, 0, iUseFlag); - VdbeComment((v, "indicate accumulator empty")); + VdbeComment((v, "indicate accumulator %d empty", p->selId)); sqlite3VdbeAddOp1(v, OP_Return, regReset); if( distFlag!=0 && eDist!=WHERE_DISTINCT_NOOP ){ |