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 university,round(count(question_id)/count(distinct(ar.device_id)),4)as avg_answer_cnt from user_profile as ar join question_practice_detail as br on ar.device_id=br.device_id group by university order by university