SQL語句查詢重復字段並按數量排序

 　　SQL語句

　　描述：exhibitiononline表主鍵exhiid， exhibitor表有外鍵 exhid，對應表 exhibitiononline的主鍵exhiid;

　　exhibitiononline表---------> 一對多 <------------- exhibitor表

　　功能：查詢出 exhibitiononline表中，exhiid存在於表 exhibitor中的所有數據，並根據 exhibitor表的exhid的數量排序

　　select * from exhibitiononline join

　　(select exhid,count(exhid) as s from exhibitor group by exhid) as t

　　on exhibitiononline.exhiid=t.exhid

　　order by t.s desc