题解 | #统计每个用户的平均刷题数#
统计每个用户的平均刷题数
https://www.nowcoder.com/practice/f4714f7529404679b7f8909c96299ac4
select university, difficult_level, count(qpd.device_id)/count(distinct qpd.question_id) avg_answer_cnt from user_profile as up inner join question_practice_detail as qpd on up.device_id = qpd.device_id inner join question_detail as qd on qpd.question_id = qd.question_id where up.university = '山东大学' group by 1,2
