清晰思路 | 统计每个用户的平均刷题数
统计每个用户的平均刷题数
https://www.nowcoder.com/practice/f4714f7529404679b7f8909c96299ac4
SELECT university,difficult_level,COUNT(qpd.question_id)/COUNT(DISTINCT qpd.device_id) FROM user_profile AS up JOIN question_practice_detail AS qpd ON up.device_id=qpd.device_id JOIN question_detail AS qd ON qpd.question_id=qd.question_id WHERE university = "山东大学" GROUP BY difficult_level;
