Hi! It looks like I found a strange behaviour of the MySQL (3.23.36 on windows and linux). Probably it's due to my own mistake but I really can't catch what's up. Look: I have two tables linked w/ the 'one-to-many' relation. They look like follows: mysql> describe MessageType; +--------------+--------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +--------------+--------------+------+-----+---------+----------------+ | Id | int(11) | | PRI | NULL | auto_increment | | Owner | int(11) | | | 0 | | | Name | varchar(30) | | | | | .... +--------------+--------------+------+-----+---------+----------------+ 12 rows in set (0.01 sec) mysql> describe Message; +------------+------------+------+-----+---------------------+----------------+ | Field | Type | Null | Key | Default | Extra | +------------+------------+------+-----+---------------------+----------------+ | Id | int(11) | | PRI | NULL | auto_increment | | Type | int(11) | | | 0 | | ... +------------+------------+------+-----+---------------------+----------------+ 4 rows in set (0.01 sec) So each message has a type, each message type has an owner (described elsewhere). Now I try to get a list w/ all message types for a particular owner w/ currently selected MessageType 'highlighted' for given owner and message (Message 8 does have type 3 and this type 3 has owner 3, believe me :-)): mysql> SELECT T.Id, T.Owner, M.Id, M.Type FROM MessageType T LEFT JOIN Message M on T.Id = M.Type and M.Id=8 where T.Owner=3; +----+-------+------+------+ | id | owner | Id | Type | +----+-------+------+------+ | 1 | 3 | NULL | NULL | | 3 | 3 | NULL | NULL | +----+-------+------+------+ 2 rows in set (0.00 sec) Quite strange, right? But if I narrow the filter I get reasonable result: mysql> SELECT T.Id, T.Owner, M.Id, M.Type FROM MessageType T LEFT JOIN Message M on T.Id = M.Type and M.Id=8 where T.Owner=3 _*AND T.Id = 3*;_ +----+-------+----+------+ | Id | Owner | Id | Type | +----+-------+----+------+ | 3 | 3 | 8 | 3 | +----+-------+----+------+ 1 row in set (0.01 sec) That's it. I can't explain such behaviour. Yours respectfully, Alexey Morozov. P.S. When replying please CC to me directly 'cause I'm not yet a member of the list. Thank you.