August 2022
Beginner to intermediate
436 pages
9h 43m
Korean
Content preview from SQL로 시작하는 데이터 분석
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145
3
장
시계열 분석
1992-03-01 2089.00 3
... ... ...
1993-01-01 2672.08 12
1993-02-01 2673.25 12
1993-03-01 2676.50 12
... ... ...
이 쿼리에서는 윈도우를 매출이 발생한 순서로 정렬하기 위해
sales
_
month
기준으로 오름차
순 정렬합니다. 우리는 매출 레코드가 월별 하나씩 존재한다는 사실을 알고 있으므로,
Frame
절에서
rows
between
11
preceding
and
current
row
를 사용해
11
개월 이전부터 지금
까지의 매출 값을 가져와 평균과 개수를 계산합니다. 이 쿼리는
11
개월 이전의 데이터가 존재
하지 않는 달의 윈도우 평균까지 모두 계산하므로, 이 레코드들을 제거하려면 해당 쿼리를 서
브쿼리로 사용하고 외부쿼리에서
11
개월 이전의 데이터가 존재하지 않는 월을 제거합니다.
TIP
많은 기업이 여러 목적으로 과거 시간부터 이동 평균을 계산하는 방법을 사용합니다.
SQL
윈도우 함수는 미
래 시간 방향으로 이동 평균을 구해 미래를 예측하는 등 꼭 시계열 분석이 아니더라도 다양한 목적으로 응용
됩니다.
시간 윈도우 롤링을 계산할 수 있을 정도로 충분한 기간의 데이터셋이 있으면
self
-
JOIN
혹은
윈도우 함수를 사용해 이동 평균을 비롯한 이동 집계 ...
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and much more.
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.