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Do not allow a WHERE clause constraint to be used to drive an index for

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the right operand of a RIGHT JOIN, since this can cause problem if the
constraint implies a not-NULL value for one of the columns for the left
operand of the same join.  See
[forum:/forumpost/206d99a16dd9212f|forum post 206d99a16dd9212f].

FossilOrigin-Name: 4a31b7942a15c9c4363477365784d6d4ac5b1bbe8ff8aeaf2dd3d6532bf8bc96
This commit is contained in:
drh
2022-06-06 15:27:42 +00:00
parent 8a4d2bc34f
commit c18fc6134e
4 changed files with 36 additions and 15 deletions
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src/where.c
+12 -6
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@@ -1177,11 +1177,11 @@ static sqlite3_index_info *allocateIndexInfo(
assert( pTerm->u.x.leftColumn<pTab->nCol );
/* tag-20191211-002: WHERE-clause constraints are not useful to the
** right-hand table of a LEFT JOIN nor to the left-hand table of a
** right-hand table of a LEFT JOIN nor to the either table of a
** RIGHT JOIN. See tag-20191211-001 for the
** equivalent restriction for ordinary tables. */
if( (pSrc->fg.jointype & (JT_LEFT|JT_LTORJ))!=0
&& !ExprHasProperty(pTerm->pExpr, EP_OuterON)
if( (pSrc->fg.jointype & (JT_LEFT|JT_LTORJ|JT_RIGHT))!=0
&& !ExprHasProperty(pTerm->pExpr, EP_OuterON|EP_InnerON)
){
continue;
}
@@ -2833,9 +2833,15 @@ static int whereLoopAddBtreeIndex(
/* tag-20191211-001: Do not allow constraints from the WHERE clause to
** be used by the right table of a LEFT JOIN nor by the left table of a
** RIGHT JOIN. Only constraints in the
** ON clause are allowed. See tag-20191211-002 for the vtab equivalent. */
if( (pSrc->fg.jointype & (JT_LEFT|JT_LTORJ))!=0
** RIGHT JOIN. Only constraints in the ON clause are allowed.
** See tag-20191211-002 for the vtab equivalent.
**
** 2022-06-06: See https://sqlite.org/forum/forumpost/206d99a16dd9212f
** for an example of a WHERE clause constraints that may not be used on
** the right table of a RIGHT JOIN because the constraint implies a
** not-NULL condition on the left table of the RIGHT JOIN.
*/
if( (pSrc->fg.jointype & (JT_LEFT|JT_LTORJ|JT_RIGHT))!=0
&& !ExprHasProperty(pTerm->pExpr, EP_OuterON|EP_InnerON)
){
continue;