[MDEV-8766] Wrong result for SELECT..WHERE LENGTH(time_column)=8 AND time_column=TIMESTAMP'2001-01-01 10:20:31' Created: 2015-09-08  Updated: 2018-08-11  Resolved: 2015-09-08

Status: Closed
Project: MariaDB Server
Component/s: Optimizer
Affects Version/s: 10.0, 10.1
Fix Version/s: 10.1.7

Type: Bug Priority: Major
Reporter: Alexander Barkov Assignee: Alexander Barkov
Resolution: Fixed Votes: 0
Labels: propagation, upstream-not-supported

Issue Links:
Blocks
blocks MDEV-8728 Fix a number of problems in equal fie... Closed

 Description    

SET timestamp=UNIX_TIMESTAMP('2001-01-01 01:02:03');
 
DROP TABLE IF EXISTS t1;
 
CREATE TABLE t1 (a TIME);
 
INSERT INTO t1 VALUES ('10:20:31'),('-10:20:31');
 
SELECT * FROM t1 WHERE a=TIMESTAMP'2001-01-01 10:20:31';
 
SELECT * FROM t1 WHERE LENGTH(a)=8;
 
SELECT * FROM t1 WHERE LENGTH(a)=8 AND a=TIMESTAMP'2001-01-01 10:20:31';

In the above script the first and the second SELECT queries correctly return one row, the third SELECT query returns erroneously no rows.

 Comments   
Comment by Alexander Barkov [ 2015-09-12 ]

MySQL-5.7.8 does not support propagation in this case:

explain extended SELECT * FROM t1 WHERE LENGTH(a)=8 AND a=TIMESTAMP'2001-01-01 10:20:31';
 
SHOW WARNINGS;
 

+---------+------+----------------------------------------------------------------------------------------------------------------------------------------+
 
| Level   | Code | Message                                                                                                                                |
 
+---------+------+----------------------------------------------------------------------------------------------------------------------------------------+
 
| Warning | 1681 | 'EXTENDED' is deprecated and will be removed in a future release.                                                                      |
 
| Note    | 1003 | /* select#1 */ select `test`.`t1`.`a` AS `a` from `test`.`t1` where ((length(`test`.`t1`.`a`) = 8) and (`test`.`t1`.`a` = '10:20:31')) |
 
+---------+------+----------------------------------------------------------------------------------------------------------------------------------------+

Generated at Thu Feb 08 07:29:37 UTC 2024 using Jira 8.20.16#820016-sha1:9d11dbea5f4be3d4cc21f03a88dd11d8c8687422.