A Database Error Occurred

Error Number: 1064

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 'AND comments.`active` =1 AND members.`id` = comments.`user_id`' at line 1

SELECT comments. * , members.user_name FROM `comments` , members WHERE comments.`topic_id` = AND comments.`active` =1 AND members.`id` = comments.`user_id`