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
device_id,
'复旦大学' as university,
coalesce(count(question_id), 0),
sum(if (result = 'right', 1, 0))
from
(
select
u.device_id,
q.question_id,
q.result
from
user_profile u
join question_practice_detail q on u.device_id = q.device_id
where
u.university = '复旦大学'
and month (q.date) = '08'
) t1
group by
device_id
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