select c.cid
,count(p.cid)
,sum(timestampdiff(minute,start_time,end_time)) time_len
from play_record_tb p
left join course_info_tb c
on p.cid = c.cid 
where date(start_time)-date(release_date) <=7
group by 1
order by 2 desc,3 desc
limit 3