题解 | 统计复旦用户8月练题情况
统计复旦用户8月练题情况
https://www.nowcoder.com/practice/53235096538a456b9220fce120c062b3
SELECT u.device_id, university, sum(case when result IS NULL then 0 else 1 end) as question_cnt, sum(case when result = 'right' then 1 else 0 end) as right_question_cnt FROM user_profile as u LEFT JOIN question_practice_detail as q ON u.device_id=q.device_id WHERE university='复旦大学' and (month(date)=8 or date is null) GROUP BY u.device_id;
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