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,count(question_id)/count(DISTINCT question_practice_detail.device_id) as avg_answer_cnt FROM question_practice_detail,user_profile WHERE user_profile.device_id=question_practice_detail.device_id GROUP BY university ORDER BY university,avg_answer_cnt;

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