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
官方的太复杂了，看我的
select
u.device_id,u.university,
count(q.question_id) as question_cnt,
sum(case when q.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
and month(q.date)=8
where u.university='复旦大学'
group by u.device_id, u.university;
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