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( COUNT(q.question_id) / COUNT(DISTINCT q.device_id) , 4 ) AS avg_answer_cnt
FROM user_profile AS u
JOIN question_practice_detail AS q
ON u.device_id = q.device_id
GROUP BY u.university
ORDER BY u.university ASC;
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