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
http://www.nowcoder.com/practice/53235096538a456b9220fce120c062b3
select b.device_id,university,count(b.question_id) as question_cnt, sum(IF(b.result="right",1,0)) as right_question_cnt from user_profile a right join question_practice_detail b on a.device_id=b.device_id and month(b.date)="08" where university="复旦大学" group by a.device_id
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