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-rw-r--r--src/select.c179
1 files changed, 93 insertions, 86 deletions
diff --git a/src/select.c b/src/select.c
index 571a77822..188050e8d 100644
--- a/src/select.c
+++ b/src/select.c
@@ -2219,8 +2219,8 @@ static int multiSelectOrderBy(
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;
+ assert( pItem->iOrderByCol>0 );
+ if( pItem->iOrderByCol==i ) break;
}
if( j==nOrderBy ){
Expr *pNew = sqlite3Expr(db, TK_INTEGER, 0);
@@ -2228,7 +2228,7 @@ static int multiSelectOrderBy(
pNew->flags |= EP_IntValue;
pNew->u.iValue = i;
pOrderBy = sqlite3ExprListAppend(pParse, pOrderBy, pNew);
- pOrderBy->a[nOrderBy++].iCol = (u16)i;
+ pOrderBy->a[nOrderBy++].iOrderByCol = (u16)i;
}
}
}
@@ -2244,8 +2244,8 @@ static int multiSelectOrderBy(
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;
+ assert( pItem->iOrderByCol>0 && pItem->iOrderByCol<=p->pEList->nExpr );
+ aPermute[i] = pItem->iOrderByCol - 1;
}
pKeyMerge =
sqlite3DbMallocRaw(db, sizeof(*pKeyMerge)+nOrderBy*(sizeof(CollSeq*)+1));
@@ -2588,9 +2588,8 @@ static void substSelect(
#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.
+** This routine attempts to flatten subqueries as a performance optimization.
+** This routine returns 1 if it makes changes and 0 if no flattening occurs.
**
** To understand the concept of flattening, consider the following
** query:
@@ -2632,7 +2631,10 @@ static void substSelect(
** (6) The subquery does not use aggregates or the outer query is not
** DISTINCT.
**
-** (7) The subquery has a FROM clause.
+** (7) The subquery has a FROM clause. TODO: For subqueries without
+** A FROM clause, consider adding a FROM close with the special
+** table sqlite_once that consists of a single row containing a
+** single NULL.
**
** (8) The subquery does not use LIMIT or the outer query is not a join.
**
@@ -2665,11 +2667,14 @@ static void substSelect(
**
** * 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.
+** * is not a join
**
** 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.
+** LIMIT and OFFSET clauses. The subquery cannot use any compound
+** operator other than UNION ALL because all the other compound
+** operators have an implied DISTINCT which is disallowed by
+** restriction (4).
**
** (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
@@ -2681,7 +2686,7 @@ static void substSelect(
** (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
+** appear as unmodified result columns in the outer query. But we
** have other optimizations in mind to deal with that case.
**
** (21) The subquery does not use LIMIT or the outer query is not
@@ -2810,19 +2815,21 @@ static int flattenSubquery(
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 );
+ assert( pSub->pSrc!=0 );
if( (pSub1->selFlags & (SF_Distinct|SF_Aggregate))!=0
|| (pSub1->pPrior && pSub1->op!=TK_ALL)
- || NEVER(pSub1->pSrc==0) || pSub1->pSrc->nSrc!=1
+ || pSub1->pSrc->nSrc<1
){
return 0;
}
+ testcase( pSub1->pSrc->nSrc>1 );
}
/* 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( p->pOrderBy->a[ii].iOrderByCol==0 ) return 0;
}
}
}
@@ -3845,12 +3852,11 @@ int sqlite3Select(
topAddr = sqlite3VdbeAddOp2(v, OP_Integer, 0, pItem->regReturn);
pItem->addrFillSub = topAddr+1;
VdbeNoopComment((v, "materialize %s", pItem->pTab->zName));
- if( pItem->isCorrelated==0 && pParse->pTriggerTab==0 ){
+ if( pItem->isCorrelated==0 ){
/* If the subquery is no correlated and if we are not inside of
** a trigger, then we only need to compute the value of the subquery
** once. */
- int regOnce = ++pParse->nMem;
- onceAddr = sqlite3VdbeAddOp1(v, OP_Once, regOnce);
+ onceAddr = sqlite3CodeOnce(pParse);
}
sqlite3SelectDestInit(&dest, SRT_EphemTab, pItem->iCursor);
explainSetInteger(pItem->iSelectId, (u8)pParse->iNextSelectId);
@@ -3860,7 +3866,7 @@ int sqlite3Select(
retAddr = sqlite3VdbeAddOp1(v, OP_Return, pItem->regReturn);
VdbeComment((v, "end %s", pItem->pTab->zName));
sqlite3VdbeChangeP1(v, topAddr, retAddr);
-
+ sqlite3ClearTempRegCache(pParse);
}
if( /*pParse->nErr ||*/ db->mallocFailed ){
goto select_end;
@@ -4155,6 +4161,7 @@ int sqlite3Select(
VdbeComment((v, "clear abort flag"));
sqlite3VdbeAddOp2(v, OP_Integer, 0, iUseFlag);
VdbeComment((v, "indicate accumulator empty"));
+ sqlite3VdbeAddOp3(v, OP_Null, 0, iAMem, iAMem+pGroupBy->nExpr-1);
/* 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
@@ -4494,98 +4501,98 @@ select_end:
return rc;
}
-#if defined(SQLITE_DEBUG)
+#if defined(SQLITE_ENABLE_TREE_EXPLAIN)
/*
-*******************************************************************************
-** 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.
+** Generate a human-readable description of a the Select object.
*/
-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(", ");
+static void explainOneSelect(Vdbe *pVdbe, Select *p){
+ sqlite3ExplainPrintf(pVdbe, "SELECT ");
+ if( p->selFlags & (SF_Distinct|SF_Aggregate) ){
+ if( p->selFlags & SF_Distinct ){
+ sqlite3ExplainPrintf(pVdbe, "DISTINCT ");
+ }
+ if( p->selFlags & SF_Aggregate ){
+ sqlite3ExplainPrintf(pVdbe, "agg_flag ");
}
+ sqlite3ExplainNL(pVdbe);
+ sqlite3ExplainPrintf(pVdbe, " ");
}
-}
-void sqlite3PrintSelect(Select *p, int indent){
- sqlite3DebugPrintf("%*sSELECT(%p) ", indent, "", p);
- sqlite3PrintExprList(p->pEList);
- sqlite3DebugPrintf("\n");
- if( p->pSrc ){
- char *zPrefix;
+ sqlite3ExplainExprList(pVdbe, p->pEList);
+ sqlite3ExplainNL(pVdbe);
+ if( p->pSrc && p->pSrc->nSrc ){
int i;
- zPrefix = "FROM";
+ sqlite3ExplainPrintf(pVdbe, "FROM ");
+ sqlite3ExplainPush(pVdbe);
for(i=0; i<p->pSrc->nSrc; i++){
struct SrcList_item *pItem = &p->pSrc->a[i];
- sqlite3DebugPrintf("%*s ", indent+6, zPrefix);
- zPrefix = "";
+ sqlite3ExplainPrintf(pVdbe, "{%d,*} = ", pItem->iCursor);
if( pItem->pSelect ){
- sqlite3DebugPrintf("(\n");
- sqlite3PrintSelect(pItem->pSelect, indent+10);
- sqlite3DebugPrintf("%*s)", indent+8, "");
+ sqlite3ExplainSelect(pVdbe, pItem->pSelect);
+ if( pItem->pTab ){
+ sqlite3ExplainPrintf(pVdbe, " (tabname=%s)", pItem->pTab->zName);
+ }
}else if( pItem->zName ){
- sqlite3DebugPrintf("%s", pItem->zName);
- }
- if( pItem->pTab ){
- sqlite3DebugPrintf("(table: %s)", pItem->pTab->zName);
+ sqlite3ExplainPrintf(pVdbe, "%s", pItem->zName);
}
if( pItem->zAlias ){
- sqlite3DebugPrintf(" AS %s", pItem->zAlias);
+ sqlite3ExplainPrintf(pVdbe, " (AS %s)", pItem->zAlias);
}
- if( i<p->pSrc->nSrc-1 ){
- sqlite3DebugPrintf(",");
+ if( pItem->jointype & JT_LEFT ){
+ sqlite3ExplainPrintf(pVdbe, " LEFT-JOIN");
}
- sqlite3DebugPrintf("\n");
+ sqlite3ExplainNL(pVdbe);
}
+ sqlite3ExplainPop(pVdbe);
}
if( p->pWhere ){
- sqlite3DebugPrintf("%*s WHERE ", indent, "");
- sqlite3PrintExpr(p->pWhere);
- sqlite3DebugPrintf("\n");
+ sqlite3ExplainPrintf(pVdbe, "WHERE ");
+ sqlite3ExplainExpr(pVdbe, p->pWhere);
+ sqlite3ExplainNL(pVdbe);
}
if( p->pGroupBy ){
- sqlite3DebugPrintf("%*s GROUP BY ", indent, "");
- sqlite3PrintExprList(p->pGroupBy);
- sqlite3DebugPrintf("\n");
+ sqlite3ExplainPrintf(pVdbe, "GROUPBY ");
+ sqlite3ExplainExprList(pVdbe, p->pGroupBy);
+ sqlite3ExplainNL(pVdbe);
}
if( p->pHaving ){
- sqlite3DebugPrintf("%*s HAVING ", indent, "");
- sqlite3PrintExpr(p->pHaving);
- sqlite3DebugPrintf("\n");
+ sqlite3ExplainPrintf(pVdbe, "HAVING ");
+ sqlite3ExplainExpr(pVdbe, p->pHaving);
+ sqlite3ExplainNL(pVdbe);
}
if( p->pOrderBy ){
- sqlite3DebugPrintf("%*s ORDER BY ", indent, "");
- sqlite3PrintExprList(p->pOrderBy);
- sqlite3DebugPrintf("\n");
+ sqlite3ExplainPrintf(pVdbe, "ORDERBY ");
+ sqlite3ExplainExprList(pVdbe, p->pOrderBy);
+ sqlite3ExplainNL(pVdbe);
+ }
+ if( p->pLimit ){
+ sqlite3ExplainPrintf(pVdbe, "LIMIT ");
+ sqlite3ExplainExpr(pVdbe, p->pLimit);
+ sqlite3ExplainNL(pVdbe);
+ }
+ if( p->pOffset ){
+ sqlite3ExplainPrintf(pVdbe, "OFFSET ");
+ sqlite3ExplainExpr(pVdbe, p->pOffset);
+ sqlite3ExplainNL(pVdbe);
+ }
+}
+void sqlite3ExplainSelect(Vdbe *pVdbe, Select *p){
+ if( p==0 ){
+ sqlite3ExplainPrintf(pVdbe, "(null-select)");
+ return;
}
+ while( p->pPrior ) p = p->pPrior;
+ sqlite3ExplainPush(pVdbe);
+ while( p ){
+ explainOneSelect(pVdbe, p);
+ p = p->pNext;
+ if( p==0 ) break;
+ sqlite3ExplainNL(pVdbe);
+ sqlite3ExplainPrintf(pVdbe, "%s\n", selectOpName(p->op));
+ }
+ sqlite3ExplainPrintf(pVdbe, "END");
+ sqlite3ExplainPop(pVdbe);
}
+
/* End of the structure debug printing code
*****************************************************************************/
#endif /* defined(SQLITE_TEST) || defined(SQLITE_DEBUG) */
generated by cgit v1.2.3 (git 2.25.1) at 2025-07-21 19:53:30 +0000