Details
-
Bug
-
Status: Closed (View Workflow)
-
Major
-
Resolution: Fixed
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None
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None
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None
Description
The following query:
SELECT *
FROM t1, t2
WHERE (t2.a , t1.b) IN (
SELECT a , b
FROM t3
);
returns the matching row twice:
-------+
| b | a |
-------+
| 5 | 6 |
| 5 | 6 |
-------+
whereas the correct result is:
-------+
| b | a |
-------+
| 5 | 6 |
-------+
explain:
----------------------------------------------------------------------------------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
----------------------------------------------------------------------------------------+
| 1 | PRIMARY | t1 | ALL | NULL | NULL | NULL | NULL | 2 | Â |
| 1 | PRIMARY | t3 | ALL | b | NULL | NULL | NULL | 5 | Using where; LooseScan |
| 1 | PRIMARY | t2 | eq_ref | PRIMARY | PRIMARY | 4 | test.t3.a | 1 | Using index |
----------------------------------------------------------------------------------------+
minimal optimizer_switch: semijoin=on,loosescan=on
full optimizer switch: index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=off,derived_merge=off,derived_with_keys=off,firstmatch=off,loosescan=on,materialization=off,in_to_exists=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=off,table_elimination=on
bzr version-info:
revision-id: <email address hidden>
date: 2011-08-23 15:51:47 +0300
build-date: 2011-08-26 17:20:27 +0300
revno: 3166
branch-nick: maria-5.3
test case:
CREATE TABLE t1 (b int) ;
INSERT INTO t1 VALUES (1),(5);
CREATE TABLE t2 (a int, PRIMARY KEY (a)) ;
INSERT INTO t2 VALUES (6),(10);
CREATE TABLE t3 (a int, b int, KEY (b)) ;
INSERT INTO t3 VALUES (6,5),(6,2),(8,0),(9,1),(6,5);
SET SESSION optimizer_switch='loosescan=on';
SELECT *
FROM t1, t2
WHERE (t2.a , t1.b) IN (
SELECT a , b
FROM t3
);