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(answer_cnt)/count(distinct u.device_id) avg_answer_cnt from question_practice_detail qpd left join question_detail qd on qpd.question_id = qd.question_id left join user_profile u on qpd.device_id = u.device_id where university = '山东大学' and answer_cnt > 0 group by difficult_level
开发你这个也没有项目啊
