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 a.university,round(count(b.question_id)/count(distinct b.device_id),4) as avg_answwer_cnt from user_profile a join question_practice_detail b //关联其他表 on a.device_id=b.device_id group by university //以学校进行分组 order by university //以学校进行排序;
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