题解 | 今天的刷题量(一)

select b.name,b.cnt
from 
(select a.subject_id,a.name,count(a.create_time) cnt
    from 
       (select s.subject_id, su.name, s.create_time 
            from submission s join subject su on s.subject_id=su.id
            where s.create_time=curdate()
       ) a
    group by a.subject_id,a.name
    order by cnt desc, a.subject_id asc
) b