Aovic info: MySQL Query Error

Time: 2012-5-22 7:04pm
Script: /blog/index.php/499/action_viewspace_itemid_77.html

SQL: SELECT * FROM blog_friends WHERE uid=499 AND frienduid=0 AND grade IN () LIMIT 1
Error: 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 '' at line 1
Errno.: 1064

Similar error report has beed dispatched to administrator before.