题解 | 中位数的问题转化成排序问题
最差是第几名(二)
https://www.nowcoder.com/practice/165d88474d434597bcd2af8bf72b24f1
select grade from (select grade,sum(number)over(order by grade) a,sum(number)over(order by grade desc) b from class_grade) t where a>=(select sum(number)/2 from class_grade) and b>=(select sum(number)/2 from class_grade) order by grade
