题解 | #统计每个学校的答过题的用户的平均答题数#
统计每个学校的答过题的用户的平均答题数
https://www.nowcoder.com/practice/88aa923a9a674253b861a8fa56bac8e5
select user_profile.university, count(question_practice_detail.question_id)/count(distinct question_practice_detail.device_id) as avg_answer_cnt from user_profile inner join question_practice_detail on user_profile.device_id = question_practice_detail.device_id group by user_profile.university order by user_profile.university asc