题解 | #最差是第几名(二)#

select a.grade
from 
(
select grade, (select sum(number) from class_grade) as sum, 
sum(number) over(order by grade asc) as start, sum(number) over(order by grade desc) as end
from class_grade
) a
where start >= sum / 2 and end >= sum / 2
order by a.grade