집계 함수 order by

with temp_01

as (

select d.category_name,

to_char(date_trunc('month', a.order_date), 'yyyymm') as month_day,

sum(amount) as sum_amount,

count(distinct a.order_id) as monthly_ord_cnt

from orders a

join order_items b on a.order_id = b.order_id

join products c on b.product_id = c.product_id

join categories d on c.category_id = d.category_id

group by d.category_name, to_char(date_trunc('month', a.order_date), 'yyyymm')

)

select *,

sum(sum_amount) over (partition by month_day order by month_day) as temp1,

sum(sum_amount) over (partition by month_day) as temp2,

sum_amount / sum(sum_amount) over (partition by month_day) as ratio

from temp_01

집계 어날리틱 함수는 order by를 사용하면 파티션 내에서 누적합이 되는것으로 알고 있었는데 왜 이렇게 나올까요...? 제가 혹시 놓친게 있는 걸까요