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Bug#47669 Query showed by EXPLAIN EXTENDED gives different result from original query

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Item_field::print method does not take into
account fields whose values may be null.
The fix is to print 'NULL' if field value is null.
This commit is contained in:
Sergey Glukhov
2010-02-26 17:40:01 +04:00
parent 3fcb25d806
commit 5d9a74f22d
8 changed files with 48 additions and 16 deletions
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15
mysql-test/r/explain.result
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@ -210,4 +210,19 @@ Error 1140 Mixing of GROUP columns (MIN(),MAX(),COUNT(),...) with no GROUP colum
Note 1003 select 1 AS `1` from `test`.`t1` where <not>(<exists>(...))
SET SESSION sql_mode=@old_sql_mode;
DROP TABLE t1;
#
# Bug#47669: Query showed by EXPLAIN EXTENDED gives different result from original query
#
CREATE TABLE t1 (c int);
INSERT INTO t1 VALUES (NULL);
CREATE TABLE t2 (d int);
INSERT INTO t2 VALUES (NULL), (0);
EXPLAIN EXTENDED SELECT (SELECT 1 FROM t2 WHERE d = c) FROM t1;
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t1 system NULL NULL NULL NULL 1 100.00
2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 2 100.00 Using where
Warnings:
Note 1276 Field or reference 'test.t1.c' of SELECT #2 was resolved in SELECT #1
Note 1003 select (select 1 AS `1` from `test`.`t2` where (`test`.`t2`.`d` = NULL)) AS `(SELECT 1 FROM t2 WHERE d = c)` from `test`.`t1`
DROP TABLE t1, t2;
End of 5.1 tests.