[TIL]Day 237

롤업은 소계를 구할 때 사용.
전체 집계도 보여줌.

sql로 누적값을 구하기
셀프조인으로도 가능하지만
select a.no,a.count_dt,max(a.download_cnt) ,sum(b.couwnload_cnt)
from ssak3 a, ssak3 b
where a.no = b.no
and a.count_dt >= b.count_dt
order by a.no, a.count_dt

select no,title, count_dt, download_cnt
,sum(download_cnt) over(partition by no order by count_dt rows between unbound preceding and corrent row)
from ssak3