题解 | 获得积分最多的人(一)

SELECT b.name,MAX(a.grade_num) grade_num
FROM(
    SELECT user_id,SUM(grade_num) OVER(partition by user_id) grade_num
    FROM grade_info
) a
INNER JOIN 
user b
ON a.user_id =b.id
GROUP BY b.name
ORDER BY grade_num DESC
LIMIT 1