Re: strange unique index behaviour on null values

Sergei Golubchik <[email protected]>
Newsgroups gmane.comp.db.mysql.bugs
Message-ID <[email protected]>
Hi!

Looks like a bug#2483.

http://bugs.mysql.com/bug.php?id=2483

Use this url to follow the progress of this issue.

(you may also add your test case there)

On Jan 26, mehdi wrote:
> hi all,
> 
> I get a very strange result from mysql when selecting null values from a 
> unique indexed innodb table.
> 
> so this is the structure and content of my table:
> 
> ##################################
> CREATE TABLE `testunique` (
>  `id` varchar(10) default NULL,
>  `a` char(2) NOT NULL default '',
>  `b` char(2) NOT NULL default '',
>  UNIQUE KEY `id` (`id`)
> ) TYPE=InnoDB;
> 
> INSERT INTO `testunique` VALUES (NULL, 'e', 'f');
> INSERT INTO `testunique` VALUES (NULL, 'v', 's');
> INSERT INTO `testunique` VALUES (NULL, 'r', 's');
> INSERT INTO `testunique` VALUES ('eee', 'f', 'f');
> ##################################
> 
> now, if I do a 
> 
> ##################################
> select * from testunique where id is null
> ##################################
> 
> I always get only the first row.
> If I remove the unique index then I get the expected result. also there is 
> no problem if I use myisam.
> I am using mysql 4.0.16 on a debian box.
> 
> thanks for your help.
> 
> bye
> 
Regards,
Sergei

-- 
   __  ___     ___ ____  __
  /  |/  /_ __/ __/ __ \/ /   Sergei Golubchik <[email protected]>
 / /|_/ / // /\ \/ /_/ / /__  MySQL AB, Senior Software Developer
/_/  /_/\_, /___/\___\_\___/  Osnabrueck, Germany
       <___/  www.mysql.com

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