Commit 7977a0c8 authored by igor@rurik.mysql.com's avatar igor@rurik.mysql.com
Browse files

Fixed bug #14927. 

A query with a group by and having clauses could return a wrong
result set if the having condition contained a constant conjunct 
evaluated to FALSE.
It happened because the pushdown condition for table with
grouping columns lost its constant conjuncts.
Pushdown conditions are always built by the function make_cond_for_table
that ignores constant conjuncts. This is apparently not correct when
constant false conjuncts are present.
parent ceef1105

mysql-test/r/having.result

+17 −0
Original line number Diff line number Diff line
@@ -141,3 +141,20 @@ SUM(a) 
6

4

DROP TABLE t1;

CREATE TABLE t1 (a int);

INSERT INTO t1 VALUES (1), (2), (1), (3), (2), (1);

SELECT a FROM t1 GROUP BY a HAVING a > 1;

a

2

3

SELECT a FROM t1 GROUP BY a HAVING 1 != 1 AND a > 1;

a

SELECT 0 AS x, a FROM t1 GROUP BY x,a HAVING x=1 AND a > 1;

x	a

EXPLAIN SELECT a FROM t1 GROUP BY a HAVING 1 != 1 AND a > 1;

id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra

1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible HAVING

EXPLAIN SELECT 0 AS x, a FROM t1 GROUP BY x,a HAVING x=1 AND a > 1;

id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra

1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible HAVING

DROP table t1;

mysql-test/t/having.test

+16 −0
Original line number Diff line number Diff line
@@ -135,4 +135,20 @@ SELECT SUM(a) FROM t1 GROUP BY a HAVING SUM(a); 


DROP TABLE t1;



#

# Bug #14927: HAVING clause containing constant false conjunct

#



CREATE TABLE t1 (a int);

INSERT INTO t1 VALUES (1), (2), (1), (3), (2), (1);



SELECT a FROM t1 GROUP BY a HAVING a > 1;

SELECT a FROM t1 GROUP BY a HAVING 1 != 1 AND a > 1;

SELECT 0 AS x, a FROM t1 GROUP BY x,a HAVING x=1 AND a > 1;



EXPLAIN SELECT a FROM t1 GROUP BY a HAVING 1 != 1 AND a > 1;

EXPLAIN SELECT 0 AS x, a FROM t1 GROUP BY x,a HAVING x=1 AND a > 1;



DROP table t1;  



# End of 4.1 tests

sql/sql_lex.cc

+2 −0
Original line number Diff line number Diff line
@@ -1074,6 +1074,7 @@ void st_select_lex::init_query() 
  item_list.empty();

  join= 0;

  where= 0;

  having= 0;

  olap= UNSPECIFIED_OLAP_TYPE;

  having_fix_field= 0;

  resolve_mode= NOMATTER_MODE;
@@ -1081,6 +1082,7 @@ void st_select_lex::init_query() 
  ref_pointer_array= 0;

  select_n_having_items= 0;

  prep_where= 0;

  prep_having= 0;

  subquery_in_having= explicit_limit= 0;

  parsing_place= NO_MATTER;

  is_item_list_lookup= 0;

sql/sql_lex.h

+1 −0
Original line number Diff line number Diff line
@@ -422,6 +422,7 @@ class st_select_lex: public st_select_lex_node 
  char *db, *db1, *table1, *db2, *table2;      	/* For outer join using .. */

  Item *where, *having;                         /* WHERE & HAVING clauses */

  Item *prep_where; /* saved WHERE clause for prepared statement processing */

  Item *prep_having;/* saved HAVING clause for prepared statement processing */

  enum olap_type olap;

  SQL_LIST	      table_list, group_list;   /* FROM & GROUP BY clauses */

  List<Item>          item_list; /* list of fields & expressions */

sql/sql_prepare.cc

+8 −2
Original line number Diff line number Diff line
@@ -1667,10 +1667,11 @@ int mysql_stmt_prepare(THD *thd, char *packet, uint packet_length, 
    for (; sl; sl= sl->next_select_in_list())

    {

      /*

        Save WHERE clause pointers, because they may be changed

        Save WHERE, HAVING clause pointers, because they may be changed

        during query optimisation.

      */

      sl->prep_where= sl->where;

      sl->prep_having= sl->having;

      /*

        Switch off a temporary flag that prevents evaluation of

        subqueries in statement prepare.
@@ -1696,13 +1697,18 @@ static void reset_stmt_for_execute(Prepared_statement *stmt) 
    /* remove option which was put by mysql_explain_union() */

    sl->options&= ~SELECT_DESCRIBE;

    /*

      Copy WHERE clause pointers to avoid damaging they by optimisation

      Copy WHERE, HAVING clause pointers to avoid damaging they by optimisation

    */

    if (sl->prep_where)

    {

      sl->where= sl->prep_where->copy_andor_structure(thd);

      sl->where->cleanup();

    }

    if (sl->prep_having)

    {

      sl->having= sl->prep_having->copy_andor_structure(thd);

      sl->having->cleanup();

    }

    DBUG_ASSERT(sl->join == 0);

    ORDER *order;

    /* Fix GROUP list */