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Bug #42760: Select doesn't return desired results when we have null

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values
 
 We should re-set the access method functions when changing the access
 method when switching to another index to avoid sorting.
 
 Fixed by doing a little re-engineering : encapsulating all the function
 assignment into a special function and calling it when flipping the 
 indexes.
This commit is contained in:
Georgi Kodinov
2009-11-10 10:21:41 +02:00
parent 58ee6c80eb
commit ddd90017e7
3 changed files with 108 additions and 50 deletions
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21
mysql-test/r/order_by.result
View File

@ -1092,3 +1092,24 @@ FROM t3;
2
NULL
DROP TABLE t1, t2, t3;
#
# Bug #42760: Select doesn't return desired results when we have null
# values
#
CREATE TABLE t1 (
a INT,
c INT,
UNIQUE KEY a_c (a,c),
KEY (a));
INSERT INTO t1 VALUES (1, 10), (2, NULL);
# Must use ref-or-null on the a_c index
EXPLAIN
SELECT 1 AS col FROM t1 WHERE a=2 AND (c=10 OR c IS NULL) ORDER BY c;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref_or_null a_c,a a_c 10 const,const 1 Using where
# Must return 1 row
SELECT 1 AS col FROM t1 WHERE a=2 AND (c=10 OR c IS NULL) ORDER BY c;
col
1
DROP TABLE t1;
End of 5.0 tests

26
mysql-test/t/order_by.test
View File

@ -756,3 +756,29 @@ SELECT
FROM t3;
DROP TABLE t1, t2, t3;
--echo #
--echo # Bug #42760: Select doesn't return desired results when we have null
--echo # values
--echo #
CREATE TABLE t1 (
a INT,
c INT,
UNIQUE KEY a_c (a,c),
KEY (a));
INSERT INTO t1 VALUES (1, 10), (2, NULL);
--echo # Must use ref-or-null on the a_c index
EXPLAIN
SELECT 1 AS col FROM t1 WHERE a=2 AND (c=10 OR c IS NULL) ORDER BY c;
--echo # Must return 1 row
SELECT 1 AS col FROM t1 WHERE a=2 AND (c=10 OR c IS NULL) ORDER BY c;
DROP TABLE t1;
--echo End of 5.0 tests