题解 | #最差是第几名(二)#

正序和逆序的序号之差为最小值的就是中位数。
取最小值的时候，我感觉自己做得有点绕了。。。
不过一时没想到应该怎么写比较清爽，大神路过帮我看下哈。

SELECT t2.grade
FROM(
    SELECT *,MIN(t.n) OVER() AS m
    FROM 
    (
        SELECT grade, ABS(SUM(number) OVER(ORDER BY grade)-SUM(number) OVER(ORDER BY grade DESC) )AS n
        FROM class_grade
    ) AS t) AS t2
WHERE t2.n=t2.m
ORDER BY grade