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,
u.university,
sum(if(q.question_id is not null, 1, 0)) as question_cnt,
sum(if(q.result = 'right', 1, 0)) 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(q.date) = '8'
group by
u.device_id,
u.university
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