MySQL Query Error select id,title,subtitle,class from dx_kskm_news where class='参考书' and ejxk_id in ('081500','081501','081502','081569','081571','081505','081503','081504','081554','081564','081568','081555','081558','081552','081570','081575','081574','081566','081572','081573','081577','081556','081557','081565','081576','081578','081506','081507','81500','81501','81503','0815Z1') order by kskm desc limit -1000,50 Warning: mysql_num_rows() expects parameter 1 to be resource, boolean given in D:\wwwroot\dddjyky\wwwroot\lanmu2.php on line 330