MySQL server error report:Array ( [0] => Array ( [message] => MySQL Query Error ) [1] => Array ( [sql] => SELECT article_id, title,open_type,cat_id,file_url, add_time, click FROM `shangchengnew`.`ecs_article` WHERE cat_id = and is_open = 1 order by click desc LIMIT 12 ) [2] => Array ( [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 'and is_open = 1 order by click desc LIMIT 12' at line 1 ) [3] => Array ( [errno] => 1064 ) )