123/www/wwwroot/xunxuetang.cn/include/db_mysqli.class.phpSELECT itemid,title,thumb,linkurl,style,catid,areaid,introduce,addtime,edittime,username,company,groupid,vip,qq,wx,ali,skype,validated,price,unit,minamount,amount FROM xxt_sell_5 WHERE status=3 AND areaid IN (31,374,375,376,377,378,379,380,381,382,383,384,385,386,387,388,389,390,391) AND catid IN (419,420,421,422,423,424,428,429,430,431,432,433,434,435,436,437,438,439) order by itemid desc LIMIT -20,20You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '-20,20' at line 1