删除重复行，效率较高的一句sql

delete a from server_business a inner join
(select serverid,businessid from server_business group by serverid,businessid having count(*)>1) b
on a.serverid=b.serverid and a.businessid=b.businessid
left join (select min(id) as id from server_business group by serverid,businessid having count(*)>1) c
on a.id=c.id where c.id is null;