题解 | #统计每个学校各难度的用户平均刷题数#
统计每个学校各难度的用户平均刷题数
https://www.nowcoder.com/practice/5400df085a034f88b2e17941ab338ee8
select u.university,qd.difficult_level,count(qpd.question_id)/count(distinct qpd.device_id) from question_practice_detail qpd inner join user_profile u on u.device_id=qpd.device_id inner join question_detail qd on qd.question_id=qpd.question_id group by u.university,qd.difficult_level;
