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Improved substitution logic in the query flattener. Saves code space, and

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(more importantly) works correctly with table-valued functions.

FossilOrigin-Name: 3d0bd95e977db50c314d33ec292f99e0539d7b4a
This commit is contained in:
drh
2015-10-11 19:46:59 +00:00
parent 48310f8c51
commit d12b636330
4 changed files with 38 additions and 42 deletions
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58
src/select.c
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@@ -3082,7 +3082,7 @@ static int multiSelectOrderBy(
#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 *);
static void substSelect(sqlite3*, Select *, int, ExprList*, int);
/*
** Scan through the expression pExpr. Replace every reference to
@@ -3119,7 +3119,7 @@ static Expr *substExpr(
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);
substSelect(db, pExpr->x.pSelect, iTable, pEList, 1);
}else{
substExprList(db, pExpr->x.pList, iTable, pEList);
}
@@ -3142,25 +3142,29 @@ 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 */
ExprList *pEList, /* Substitute values */
int doPrior /* Do substitutes on p->pPrior too */
){
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);
do{
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);
pSrc = p->pSrc;
if( pSrc ){
for(i=pSrc->nSrc, pItem=pSrc->a; i>0; i--, pItem++){
substSelect(db, pItem->pSelect, iTable, pEList, 1);
if( pItem->fg.isTabFunc ){
substExprList(db, pItem->u1.pFuncArg, iTable, pEList);
}
}
}
}
}while( doPrior && (p = p->pPrior)!=0 );
}
#endif /* !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) */
@@ -3312,7 +3316,7 @@ static int flattenSubquery(
int subqueryIsAgg /* True if the subquery uses aggregate functions */
){
const char *zSavedAuthContext = pParse->zAuthContext;
Select *pParent;
Select *pParent; /* Current UNION ALL term of the other query */
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 */
@@ -3607,9 +3611,9 @@ static int flattenSubquery(
**
** 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.
** block of code will expand the outer query FROM clause 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);
@@ -3648,11 +3652,6 @@ static int flattenSubquery(
pList->a[i].zName = zName;
}
}
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 ){
/* At this point, any non-zero iOrderByCol values indicate that the
** ORDER BY column expression is identical to the iOrderByCol'th
@@ -3672,27 +3671,20 @@ static int flattenSubquery(
assert( pSub->pPrior==0 );
pParent->pOrderBy = 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;
}
pWhere = sqlite3ExprDup(db, pSub->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);
}
substSelect(db, pParent, iParent, pSub->pEList, 0);
/* The flattened query is distinct if either the inner or the
** outer query is distinct.