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Fixed bug #28571. Outer join queries with ON conditions over

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constant outer tables did not return null complemented
rows when conditions were evaluated to FALSE.
Wrong results were returned because the conditions over constant
outer tables, when being pushed down, were erroneously enclosed 
into the guard function used for WHERE conditions.
This commit is contained in:
igor@olga.mysql.com
2007-05-26 10:33:01 -07:00
parent dc32ee5347
commit fbebb47efe
3 changed files with 60 additions and 25 deletions
Download Patch File Download Diff File Expand all files Collapse all files

15
mysql-test/r/join_outer.result
View File

@ -1239,3 +1239,18 @@ Handler_read_prev 0
Handler_read_rnd 0
Handler_read_rnd_next 6
DROP TABLE t1,t2;
CREATE TABLE t1 (c int PRIMARY KEY, e int NOT NULL);
INSERT INTO t1 VALUES (1,0), (2,1);
CREATE TABLE t2 (d int PRIMARY KEY);
INSERT INTO t2 VALUES (1), (2), (3);
EXPLAIN SELECT * FROM t1 LEFT JOIN t2 ON e<>0 WHERE c=1 AND d IS NULL;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 const PRIMARY PRIMARY 4 const 1
1 SIMPLE t2 index NULL PRIMARY 4 NULL 3 Using where; Using index; Not exists
SELECT * FROM t1 LEFT JOIN t2 ON e<>0 WHERE c=1 AND d IS NULL;
c e d
1 0 NULL
SELECT * FROM t1 LEFT JOIN t2 ON e<>0 WHERE c=1 AND d<=>NULL;
c e d
1 0 NULL
DROP TABLE t1,t2;

16
mysql-test/t/join_outer.test
View File

@ -845,3 +845,19 @@ SELECT t1.id, a FROM t1 LEFT JOIN t2 ON t1.id=t2.id WHERE t2.b IS NULL;
show status like 'Handler_read%';
DROP TABLE t1,t2;
#
# Bug 28571: outer join with false on condition over constant tables
#
CREATE TABLE t1 (c int PRIMARY KEY, e int NOT NULL);
INSERT INTO t1 VALUES (1,0), (2,1);
CREATE TABLE t2 (d int PRIMARY KEY);
INSERT INTO t2 VALUES (1), (2), (3);
EXPLAIN SELECT * FROM t1 LEFT JOIN t2 ON e<>0 WHERE c=1 AND d IS NULL;
SELECT * FROM t1 LEFT JOIN t2 ON e<>0 WHERE c=1 AND d IS NULL;
SELECT * FROM t1 LEFT JOIN t2 ON e<>0 WHERE c=1 AND d<=>NULL;
DROP TABLE t1,t2;

54
sql/sql_select.cc
View File

@ -5666,28 +5666,6 @@ make_join_select(JOIN *join,SQL_SELECT *select,COND *cond)
join->const_table_map,
(table_map) 0);
DBUG_EXECUTE("where",print_where(const_cond,"constants"););
for (JOIN_TAB *tab= join->join_tab+join->const_tables;
tab < join->join_tab+join->tables ; tab++)
{
if (*tab->on_expr_ref)
{
JOIN_TAB *cond_tab= tab->first_inner;
COND *tmp= make_cond_for_table(*tab->on_expr_ref,
join->const_table_map,
( table_map) 0);
if (!tmp)
continue;
tmp= new Item_func_trig_cond(tmp, &cond_tab->not_null_compl);
if (!tmp)
DBUG_RETURN(1);
tmp->quick_fix_field();
cond_tab->select_cond= !cond_tab->select_cond ? tmp :
new Item_cond_and(cond_tab->select_cond,tmp);
if (!cond_tab->select_cond)
DBUG_RETURN(1);
cond_tab->select_cond->quick_fix_field();
}
}
if (const_cond && !const_cond->val_int())
{
DBUG_PRINT("info",("Found impossible WHERE condition"));
@ -5918,13 +5896,39 @@ make_join_select(JOIN *join,SQL_SELECT *select,COND *cond)
}
/*
Push down all predicates from on expressions.
Each of these predicated are guarded by a variable
Push down conditions from all on expressions.
Each of these conditions are guarded by a variable
that turns if off just before null complemented row for
outer joins is formed. Thus, the predicates from an
outer joins is formed. Thus, the condition from an
'on expression' are guaranteed not to be checked for
the null complemented row.
*/
/* First push down constant conditions from on expressions */
for (JOIN_TAB *tab= join->join_tab+join->const_tables;
tab < join->join_tab+join->tables ; tab++)
{
if (*tab->on_expr_ref)
{
JOIN_TAB *cond_tab= tab->first_inner;
COND *tmp= make_cond_for_table(*tab->on_expr_ref,
join->const_table_map,
(table_map) 0);
if (!tmp)
continue;
tmp= new Item_func_trig_cond(tmp, &cond_tab->not_null_compl);
if (!tmp)
DBUG_RETURN(1);
tmp->quick_fix_field();
cond_tab->select_cond= !cond_tab->select_cond ? tmp :
new Item_cond_and(cond_tab->select_cond,tmp);
if (!cond_tab->select_cond)
DBUG_RETURN(1);
cond_tab->select_cond->quick_fix_field();
}
}
/* Push down non-constant conditions from on expressions */
JOIN_TAB *last_tab= tab;
while (first_inner_tab && first_inner_tab->last_inner == last_tab)
{