스파르타 코딩클럽 SQL 4주차 개발일지

select a.enrolled_id, b.done_cnt, a.total_cnt, round((b.done_cnt / a.total_cnt),2) as ratio from(
select enrolled_id, count(*) as total_cnt from enrolleds_detail 
group by enrolled_id
) a 

inner join (
select enrolled_id, count(*) as done_cnt from enrolleds_detail
where done = 1
group by enrolled_id
) b on a.enrolled_id = b.enrolled_id