MySQL Query Error select id,title,subtitle,class from dx_kskm_news where class='参考书' and ejxk_id in ('090203','090201','090202','090250','090200','090256','090264','090265','090253','090259','090255','090258','090251','090260','090261','090252','090257','090263','090266','090267','090249') order by kskm desc limit -2250,50 Warning: mysql_num_rows() expects parameter 1 to be resource, boolean given in D:\wwwroot\dddjyky\wwwroot\lanmu2.php on line 330