题解 | 获得积分最多的人(二)

SELECT b.user_id,c.name,b.grade_num
FROM(
    SELECT 
    a.user_id,
    a.grade_num,
    DENSE_RANK() OVER(order by a.grade_num DESC) r_l
    FROM(
        SELECT 
        user_id,
        SUM(grade_num) grade_num
        FROM grade_info 
        GROUP BY user_id) a
) b
LEFT JOIN user c
ON b.user_id = c.id
WHERE b.r_l = 1