帝国cms全站随机调取信息sql

select * from phome_ecms_news as t1 join (select round(rand() * ((select max(id) from phome_ecms_news )-(select min(id) from phome_ecms_news ))+(select min(id) from phome_ecms_news )) as id) as t2 where t1.id >= t2.id and t1.classid in(9,10,11) order by t1.id