분석함수

그룹단위로 지정건수만큼 레코드를 취득한다.(2건씩)

select
 id, pw, row_number
from (
select
 id, pw, row_number() over (partition by sex order by id) as row_number
from member
)
where row_number <= 2;

 

그룹단위로 레코드의 건수를 취득한다.

select
 id, sex, count(*) over (partition by sex) as count
from member