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
-- 这竟然是困不敢相信。。。 select device_id,max(university) university, count(case when month(date)=8 then 1 else null end) question_cnt, sum(case when month(date)=8 and result='right' then 1 else 0 end ) as right_question_cnt from (select u.*,q.question_id,q.result,q.date from user_profile u left join question_practice_detail q using(device_id) where u.university = '复旦大学') t group by device_id
