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 uni as university,round(count(que)/count(distinct dev),4) as avg_answer_cnt from ( select u.device_id as dev,u.university as uni,question_id as que from user_profile as u join ( select device_id,question_id from question_practice_detail ) as q on u.device_id=t.q.device_id ) as t group by uni order by uni
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