select * from
(
    select *, order_no=max(score)over(partition by class) from tb
)
order by order_no desc, class

select * from stu a order by (select max(score) from stu where class=a.class) desc


select a.* from stu a
inner join (select max(score) ms,class from stu group by class) b
   on a.class=b.class
   order by b.ms desc

etc.

select * from tb order by class , score desc

-->上面2005，2000：
select * from
(
    select *, order_no=(select max(score) from tb where class=a.class) from tb as a
) as t -->上面漏了别名

select S.*
from stu S join (select class, score=max(score) from stu group by class) O on S.class=O.class
order by O.score desc

select * from (
select S.*,(select max(score) from stu O where S.class=O.class) as 最高分
from stu S) as aa
order by aa.最高分 asc