MySQL Query Error select id,title,subtitle,class from dx_kskm_news where class='参考书' and ejxk_id in ('090501','090502','090504','090551','090500','090564','090562','090563','090554','090557','090555','090552','090561','090560','090556','090558','090559','090566','090567','0905Z4') order by kskm desc limit -1600,50 Warning: mysql_num_rows() expects parameter 1 to be resource, boolean given in D:\wwwroot\dddjyky\wwwroot\lanmu2.php on line 330