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Overview
Comment:Fix a problem handling sub-queries with both a correlated WHERE clause and a "HAVING 0" clause where the parent query is itself an aggregate. The problem was apparently introduced by check-in [6e6b3729e0549de0]
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Timelines: family | ancestors | descendants | both | branch-3.34
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SHA3-256: 30a4c323650cc9498a6dacd1760dd5170d7cc7848c4e96ff6bd64da365f96366
User & Date: drh 2021-01-19 20:09:44
Context
2021-01-19
20:17
Bump the version number to 3.34.1. (check-in: cea7d0f8 user: drh tags: branch-3.34)
20:09
Fix a problem handling sub-queries with both a correlated WHERE clause and a "HAVING 0" clause where the parent query is itself an aggregate. The problem was apparently introduced by check-in [6e6b3729e0549de0] (check-in: 30a4c323 user: drh tags: branch-3.34)
20:04
Prevent potential segfault in the sqlite-expert idxPopulateStat1 context cleanup code. (check-in: 69e31d52 user: drh tags: branch-3.34)
2020-12-22
16:23
Fix a problem handling sub-queries with both a correlated WHERE clause and a "HAVING 0" clause where the parent query is itself an aggregate. The problem was apparently introduced by check-in [6e6b3729e0549de0] (check-in: f62f983b user: dan tags: trunk)
Changes
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Changes to src/select.c.

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** sub-expression matches the criteria for being moved to the WHERE
** clause. If so, add it to the WHERE clause and replace the sub-expression
** within the HAVING expression with a constant "1".
*/
static int havingToWhereExprCb(Walker *pWalker, Expr *pExpr){
  if( pExpr->op!=TK_AND ){
    Select *pS = pWalker->u.pSelect;
    if( sqlite3ExprIsConstantOrGroupBy(pWalker->pParse, pExpr, pS->pGroupBy) ){


      sqlite3 *db = pWalker->pParse->db;
      Expr *pNew = sqlite3Expr(db, TK_INTEGER, "1");
      if( pNew ){
        Expr *pWhere = pS->pWhere;
        SWAP(Expr, *pNew, *pExpr);
        pNew = sqlite3ExprAnd(pWalker->pParse, pWhere, pNew);
        pS->pWhere = pNew;







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** sub-expression matches the criteria for being moved to the WHERE
** clause. If so, add it to the WHERE clause and replace the sub-expression
** within the HAVING expression with a constant "1".
*/
static int havingToWhereExprCb(Walker *pWalker, Expr *pExpr){
  if( pExpr->op!=TK_AND ){
    Select *pS = pWalker->u.pSelect;
    if( sqlite3ExprIsConstantOrGroupBy(pWalker->pParse, pExpr, pS->pGroupBy) 
     && ExprAlwaysFalse(pExpr)==0
    ){
      sqlite3 *db = pWalker->pParse->db;
      Expr *pNew = sqlite3Expr(db, TK_INTEGER, "1");
      if( pNew ){
        Expr *pWhere = pS->pWhere;
        SWAP(Expr, *pNew, *pExpr);
        pNew = sqlite3ExprAnd(pWalker->pParse, pWhere, pNew);
        pS->pWhere = pNew;

Changes to test/having.test.

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  2 "SELECT a, sum(b) FROM t1 GROUP BY a HAVING sum(b)>5 AND a=2"
    "SELECT a, sum(b) FROM t1 WHERE a=2 GROUP BY a HAVING sum(b)>5"

  3 "SELECT a, sum(b) FROM t1 GROUP BY a COLLATE binary HAVING a=2"
    "SELECT a, sum(b) FROM t1 WHERE a=2 GROUP BY a COLLATE binary"

  5 "SELECT a, sum(b) FROM t1 GROUP BY a COLLATE binary HAVING 0"
    "SELECT a, sum(b) FROM t1 WHERE 0 GROUP BY a COLLATE binary"

  6 "SELECT count(*) FROM t1,t2 WHERE a=c GROUP BY b, d HAVING b=d"
    "SELECT count(*) FROM t1,t2 WHERE a=c AND b=d GROUP BY b, d"

  7 {
      SELECT count(*) FROM t1,t2 WHERE a=c GROUP BY b, d 
      HAVING b=d COLLATE nocase
................................................................................
# If the term where moved, the query above would return the same
# result as the following. But it does not.
#
set ::nondeter_ret 0
do_execsql_test 4.3 {
  SELECT a, sum(b) FROM t3 WHERE nondeter(a) GROUP BY a
} {1 4 2 2}






















finish_test







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  2 "SELECT a, sum(b) FROM t1 GROUP BY a HAVING sum(b)>5 AND a=2"
    "SELECT a, sum(b) FROM t1 WHERE a=2 GROUP BY a HAVING sum(b)>5"

  3 "SELECT a, sum(b) FROM t1 GROUP BY a COLLATE binary HAVING a=2"
    "SELECT a, sum(b) FROM t1 WHERE a=2 GROUP BY a COLLATE binary"

  5 "SELECT a, sum(b) FROM t1 GROUP BY a COLLATE binary HAVING 1"
    "SELECT a, sum(b) FROM t1 WHERE 1 GROUP BY a COLLATE binary"

  6 "SELECT count(*) FROM t1,t2 WHERE a=c GROUP BY b, d HAVING b=d"
    "SELECT count(*) FROM t1,t2 WHERE a=c AND b=d GROUP BY b, d"

  7 {
      SELECT count(*) FROM t1,t2 WHERE a=c GROUP BY b, d 
      HAVING b=d COLLATE nocase
................................................................................
# If the term where moved, the query above would return the same
# result as the following. But it does not.
#
set ::nondeter_ret 0
do_execsql_test 4.3 {
  SELECT a, sum(b) FROM t3 WHERE nondeter(a) GROUP BY a
} {1 4 2 2}

#-------------------------------------------------------------------------
reset_db
do_execsql_test 5.0 {
  CREATE TABLE t1(a, b);
  CREATE TABLE t2(x, y);
  INSERT INTO t1 VALUES('a', 'b');
}

# The WHERE clause (a=2), uses an aggregate column from the outer query.
# If the HAVING term (0) is moved into the WHERE clause in this case,
# SQLite would at one point optimize (a=2 AND 0) to simply (0). Which
# is logically correct, but happened to cause problems in aggregate
# processing for the outer query. This test case verifies that those 
# problems are no longer present.
do_execsql_test 5.1 {
  SELECT min(b), (
    SELECT x FROM t2 WHERE a=2 GROUP BY y HAVING 0
  ) FROM t1;
} {b {}}


finish_test