题解 | #统计复旦用户8月练题情况#

select
u.device_id,
u.university,
sum(case when month(q.date) = 8 then 1 else 0 end) as question_cnt,
sum(case when month(q.date) = 8 and q.result = 'right' then 1 else 0 end) as right_question_cnt
from
question_practice_detail q
right join
user_profile u
on
q.device_id = u.device_id
where
u.university = '复旦大学'
group by
u.device_id,
u.university ;