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* Bug #20792: Incorrect results from aggregate subquery

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When processing aggregate functions all tables values are reset
to NULLs at the end of each group. 
When doing that if there are no rows found for a group
the const tables must not be reset as they are not recalculated 
by do_select()/sub_select() for each group.


mysql-test/r/subselect2.result:
  * Bug #20792: Incorrect results from aggregate subquery
   - test suite for the bug. This is dependent on InnoDB despite
     the fact that the bug and the fix are not InnoDB specific.
     This is because of the table flag HA_NOT_EXACT_COUNT.
     When this flag is off (as in MyISAM) both t2 and t3 become of
     join type 'system' as they are estimated to have 1 record and
     and this statistics can be trusted (according to the absence of
     HA_NOT_EXACT_COUNT).
mysql-test/t/subselect2.test:
  * Bug #20792: Incorrect results from aggregate subquery
   - test suite for the bug
sql/sql_select.cc:
  * Bug #20792: Incorrect results from aggregate subquery
   - when clearing results if there are not rows found for group
     the const tables must not be reset as they are not recalculated
     for each group.
This commit is contained in:
unknown 2006-07-26 19:19:30 +03:00
parent 5a77e566ab
commit 6b75e24b73
3 changed files with 38 additions and 2 deletions
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12
mysql-test/r/subselect2.result
View File

@ -130,3 +130,15 @@ id select_type table type possible_keys key key_len ref rows Extra
5 DEPENDENT SUBQUERY t3 unique_subquery PRIMARY,FFOLDERID_IDX PRIMARY 32 func 1 Using index; Using where
6 DEPENDENT SUBQUERY t3 unique_subquery PRIMARY,FFOLDERID_IDX,CMFLDRPARNT_IDX PRIMARY 32 func 1 Using index; Using where
drop table t1, t2, t3, t4;
CREATE TABLE t1 (a int(10) , PRIMARY KEY (a)) Engine=InnoDB;
INSERT INTO t1 VALUES (1),(2);
CREATE TABLE t2 (a int(10), PRIMARY KEY (a)) Engine=InnoDB;
INSERT INTO t2 VALUES (1);
CREATE TABLE t3 (a int(10), b int(10), c int(10),
PRIMARY KEY (a)) Engine=InnoDB;
INSERT INTO t3 VALUES (1,2,1);
SELECT t1.* FROM t1 WHERE (SELECT COUNT(*) FROM t3,t2 WHERE t3.c=t2.a
and t2.a='1' AND t1.a=t3.b) > 0;
a
2
DROP TABLE t1,t2,t3;

18
mysql-test/t/subselect2.test
View File

@ -150,3 +150,21 @@ EXPLAIN SELECT t2.*, t4.DOCTYPENAME, t1.CONTENTSIZE,t1.MIMETYPE FROM t2 INNER JO
drop table t1, t2, t3, t4;
# End of 4.1 tests
#
# Bug #20792: Incorrect results from aggregate subquery
#
CREATE TABLE t1 (a int(10) , PRIMARY KEY (a)) Engine=InnoDB;
INSERT INTO t1 VALUES (1),(2);
CREATE TABLE t2 (a int(10), PRIMARY KEY (a)) Engine=InnoDB;
INSERT INTO t2 VALUES (1);
CREATE TABLE t3 (a int(10), b int(10), c int(10),
PRIMARY KEY (a)) Engine=InnoDB;
INSERT INTO t3 VALUES (1,2,1);
SELECT t1.* FROM t1 WHERE (SELECT COUNT(*) FROM t3,t2 WHERE t3.c=t2.a
and t2.a='1' AND t1.a=t3.b) > 0;
DROP TABLE t1,t2,t3;

10
sql/sql_select.cc
View File

@ -4452,10 +4452,16 @@ return_zero_rows(JOIN *join, select_result *result,TABLE_LIST *tables,
DBUG_RETURN(0);
}
/*
used only in JOIN::clear
*/
static void clear_tables(JOIN *join)
{
for (uint i=0 ; i < join->tables ; i++)
/*
must clear only the non-const tables, as const tables
are not re-calculated.
*/
for (uint i=join->const_tables ; i < join->tables ; i++)
mark_as_null_row(join->table[i]); // All fields are NULL
}