| Bug #59448 | incorrect 2-table update | ||
|---|---|---|---|
| Submitted: | 12 Jan 2011 15:04 | Modified: | 17 Jan 2011 19:17 |
| Reporter: | ttt ttt | Email Updates: | |
| Status: | Not a Bug | Impact on me: | |
| Category: | MySQL Server: General | Severity: | S3 (Non-critical) |
| Version: | 5.0.51 | OS: | Any |
| Assigned to: | CPU Architecture: | Any | |
[17 Jan 2011 19:17]
Sveta Smirnova
Thank you for taking the time to write to us, but this is not a bug. Please double-check the documentation available at http://dev.mysql.com/doc/ and the instructions on how to report a bug at http://bugs.mysql.com/how-to-report.php Please read at http://dev.mysql.com/doc/refman/5.0/en/update.html: Single-table UPDATE assignments are generally evaluated from left to right. For multiple-table updates, there is no guarantee that assignments are carried out in any particular order.
Description: incorrect access order How to repeat: CREATE TABLE `test` ( `id` int(11) NOT NULL auto_increment, `a` int(11) NOT NULL, `b` int(11) NOT NULL, PRIMARY KEY (`id`)) ENGINE=MyISAM CREATE TABLE `test2` LIKE `test` REPLACE INTO `test` (`id`, `a`, `b`) VALUES ('1', '1', '1'), ('2', '1', '1'); REPLACE INTO `test2` (`id`, `a`, `b`) VALUES ('1', '1', '1'), ('2', '1', '1'); UPDATE `test2`,`test` SET `test2`.`a`=`test`.`a`+1, `test2`.`b`=`test2`.`a` WHERE `test2`.`id`=`test`.`id` AND `test`.`id`=2 UPDATE `test`,`test2` SET `test2`.`a`=`test`.`a`+1, `test2`.`b`=`test2`.`a` WHERE `test2`.`id`=`test`.`id` AND `test`.`id`=1 result id a b 1 2 1 2 2 2