题解 | 统计复旦用户8月练题情况

select up.device_id,up.university,
sum(case when qpd.date regexp '[0-9]{4}(-)[0][8]' then 1 else 0 end) as question_cnt,
sum(case when qpd.result = 'right' then 1 else 0 end) as right_question_cnt
from user_profile up
left join question_practice_detail qpd
on up.device_id = qpd.device_id
where up.university = '复旦大学'
group by up.device_id,up.university;