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Bug #49512 : subquery with aggregate function crash

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subselect_single_select_engine::exec()

When a subquery doesn't need to be evaluated because
it returns only aggregate functions and these aggregates
can be calculated from the metadata about the table it
was not updating all the relevant members of the JOIN 
structure to reflect that this is a constant query.
This caused problems to the enclosing subquery 
('<> SOME' in the test case above) trying to read some
data about the tables.

Fixed by setting const_tables to the number of tables 
when the SELECT is optimized away.
This commit is contained in:
Georgi Kodinov 2009-12-23 17:11:22 +02:00
parent 2fa49930ca
commit d2f61748cd
3 changed files with 29 additions and 0 deletions
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13
mysql-test/r/subselect.result
View File

@ -4602,4 +4602,17 @@ SELECT 1 FROM t1 GROUP BY
1
1
DROP TABLE t1;
#
# Bug #49512 : subquery with aggregate function crash
# subselect_single_select_engine::exec()
CREATE TABLE t1(a INT);
INSERT INTO t1 VALUES();
# should not crash
SELECT 1 FROM t1 WHERE a <> SOME
(
SELECT MAX((SELECT a FROM t1 LIMIT 1)) AS d
FROM t1,t1 a
);
1
DROP TABLE t1;
End of 5.1 tests.

15
mysql-test/t/subselect.test
View File

@ -3585,4 +3585,19 @@ SELECT 1 FROM t1 GROUP BY
(SELECT LAST_INSERT_ID() FROM t1 ORDER BY MIN(a) ASC LIMIT 1);
DROP TABLE t1;
--echo #
--echo # Bug #49512 : subquery with aggregate function crash
--echo # subselect_single_select_engine::exec()
CREATE TABLE t1(a INT);
INSERT INTO t1 VALUES();
--echo # should not crash
SELECT 1 FROM t1 WHERE a <> SOME
(
SELECT MAX((SELECT a FROM t1 LIMIT 1)) AS d
FROM t1,t1 a
);
DROP TABLE t1;
--echo End of 5.1 tests.

1
sql/sql_select.cc
View File

@ -942,6 +942,7 @@ JOIN::optimize()
DBUG_PRINT("info",("Select tables optimized away"));
zero_result_cause= "Select tables optimized away";
tables_list= 0; // All tables resolved
const_tables= tables;
/*
Extract all table-independent conditions and replace the WHERE
clause with them. All other conditions were computed by opt_sum_query