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 u.university,round(sum(t.question) / count(t.device_id),4) as 'avg_answer_cnt' from user_profile u left join (select device_id,count(question_id) as 'question' from question_practice_detail group by device_id) t on u.device_id = t.device_id group by u.university having avg_answer_cnt is not null order by u.university asc
