August 2022
Beginner to intermediate
436 pages
9h 43m
Korean
Content preview from SQL로 시작하는 데이터 분석
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402
SQL로 시작하는 데이터 분석
NOTE
_ 이 데이터셋에는
platform
,
genre
필드의 값이
null
인 레코드는 없지만,
publisher
필드의 값
이
null
인 레코드는 여러 개 저장돼 있습니다. 따라서
platform
필드의 값이
PS3
이고 나머지 두 필드가
All
인 값이 두 개 출력됐습니다. 나머지 두 필드의 값이 실제로
null
인 경우의
global
_
sales
합계(
0
.
55
)와
나머지 두 필드의 값에 상관없이
platform
필드의 값이
null
인 모든 경우의
global
_
sales
합계(
957
.
84
)
가 하나씩 출력된 것입니다. 마찬가지로,
genre
필드의 값이
Action
인 경우에도 나머지 두 필드가
All
인
결과가 두 개 출력됩니다. 반대로,
publisher
필드가
Atari
인 경우에는 나머지 두 필드가
All
인 경우가
하나만 출력됩니다. 이는
platform
과
genre
필드에는 값이
null
인 레코드가 없으므로
publisher
필드의
값이
Atari
인 모든 레코드의
global
_
sales
합계(
157
.
22
)만 출력된 것입니다.
cube
대신
rollup
을 사용하면 괄호 안에 표기된 필드의 모든 조합이 아니라 명시된 필드 순서
에 기반한 조합으로 그룹화해 집계합니다.
rollup
은 다음과 같이 사용합니다.
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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.