题解 | #统计复旦用户8月练题情况#

select 
u.device_id,
university,
sum(if(MONTH(date)=8,1,0)) as question_cnt,
sum(if(MONTH(date)=8 and result = 'right',1,0)) as right_question_cnt
from 
user_profile u
left join question_practice_detail q on u.device_id=q.device_id
where
university = '复旦大学' 
group by u.device_id
order by device_id asc