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(if(result is null,0,1)) question_cnt, sum(if(result='right',1,0)) right_question_cnt from user_profile u left join question_practice_detail q on u.device_id=q.device_id and month(q.date)=8 where university='复旦大学' group by u.device_id,university
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