MySQL returned error

Error Description :

Error No : 1064
Description : 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 ') GROUP BY product.id ORDER BY RAND() limit 0,20' at line 1

SQL Query
SELECT `product`.* FROM `product` WHERE id!=0 AND product.id!=203 and category_id IN () GROUP BY product.id ORDER BY RAND() limit 0,20