题解 | #作答试卷得分大于过80的人的用户等级分布#

SELECT u.level, count(u.level) level_cnt
FROM exam_record r
RIGHT JOIN examination_info i
ON r.exam_id = i.exam_id
RIGHT JOIN user_info u
ON u.uid = r.uid
WHERE r.score in (
    SELECT r.score
    FROM exam_record r
    RIGHT JOIN examination_info i
    ON i.exam_id = r.exam_id
    WHERE i.tag = 'SQL'
    AND r.score > 80
)
GROUP BY u.level
ORDER BY level_cnt DESC;