一个SQL的问题，求高手来告知一下

我的SQL语句如下：

alter table student
add rank int
go
update student
set rank=(select count(score) from student where score<=92)
from student
显示结果为

sno sname sclass score rank

u200815712 杨豪 802 85 3
u200815713 杨杰夫 802 78 3
u200815715 杨杰夫 802 92 3

希望高手能帮我解决下，达到按照分数排序的目的，还是运用这个结构，

谢谢了啊。

alter table student
add rank int
go

update student set rank=a.orderno from(
select sno,RANK() OVER (ORDER BY score desc) as orderno from student where score<=92 )a
where student.sno=a.sno

select rownum() from student where score<=92 order by score;