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Simplify the query flattener so that it does not duplicate the WHERE clause

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of subquery that is being incorporated into the outer query - copies it
directly.  This is more efficient.  And it also fixes the specific test case
show for ticket [f09fcd17810f65f71789525] but it does not resolve the more
general problem that sqlite3ExprDup() does not correctly duplicate expressions
that contain subqueries with window functions.

FossilOrigin-Name: f1b18d44ff855573542c1947a42d4025dff54cacc13dac14d044521762ea9736
This commit is contained in:
drh
2018-12-06 19:15:36 +00:00
parent d5b44d60c7
commit 11df7d2839
4 changed files with 27 additions and 9 deletions
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4
src/select.c
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@@ -3461,6 +3461,7 @@ static Expr *substExpr(
ifNullRow.iTable = pSubst->iNewTable;
pCopy = &ifNullRow;
}
testcase( ExprHasProperty(pCopy, EP_Subquery) );
pNew = sqlite3ExprDup(db, pCopy, 0);
if( pNew && pSubst->isLeftJoin ){
ExprSetProperty(pNew, EP_CanBeNull);
@@ -4025,7 +4026,8 @@ static int flattenSubquery(
pParent->pOrderBy = pOrderBy;
pSub->pOrderBy = 0;
}
pWhere = sqlite3ExprDup(db, pSub->pWhere, 0);
pWhere = pSub->pWhere;
pSub->pWhere = 0;
if( isLeftJoin>0 ){
setJoinExpr(pWhere, iNewParent);
}