mysql> SELECT * FROM yabbse_messages_current ms LEFT JOIN yabbse_post_text_current mt ON (ms.ID_MSG=mt.ID_MSG) WHERE ms.ID_TOPIC=89525;
+---------+----------+-----------+---------+------------+----------------------------+------------+------------+----------------+--------------+--------------+-------+------+----------------+--------------------+---------+---------+-------+
| ID_MSG  | ID_TOPIC | ID_MEMBER | subject | posterName | posterEmail                | posterTime | posterIP   | smiliesEnabled | modifiedTime | modifiedName | body  | icon | attachmentSize | attachmentFilename | ID_MSG  | subject | body  |
+---------+----------+-----------+---------+------------+----------------------------+------------+------------+----------------+--------------+--------------+-------+------+----------------+--------------------+---------+---------+-------+
| 3378413 |    89525 |         2 | as df   | admin      | webmaster@arf.com | 1165613195 | 88.11.15.6 |              1 |         NULL | NULL         | as df | xx   |              0 | NULL               | 3378413 | as df   | as df | 
+---------+----------+-----------+---------+------------+----------------------------+------------+------------+----------------+--------------+--------------+-------+------+----------------+--------------------+---------+---------+-------+
1 row in set (0.00 sec)

mysql> DELETE FROM yabbse_messages_current ms LEFT JOIN yabbse_post_text_current mt ON (ms.ID_MSG=mt.ID_MSG) WHERE ms.ID_TOPIC=89525;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'LEFT JOIN yabbse_post_text_current mt ON (ms.ID_MSG=mt.ID_MSG) WHERE ms.ID_TOPIC' at line 1
mysql>