August 2022
Beginner to intermediate
436 pages
9h 43m
Korean
Content preview from SQL로 시작하는 데이터 분석
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99
3
장
시계열 분석
요약하면, 시간대는 타임스탬프를 다루는 데 필수 요소이며, 데이터가 저장된 시간대를 원하는
대로 변환하려면 시간대 변환 함수를 활용합니다. 다음 절에서는
SQL
로 날짜와 타임스탬프를
다루는 방법을 알아봅니다.
3.1.2
날짜 및 타임스탬프 형식 변환
날짜 및 시간 데이터는 시계열 분석에 중요한 요소입니다. 데이터베이스에서는 날짜와 시간이
매우 다양한 방식으로 표현되므로 시계열 분석에서 날짜 형식 변환은 피할 수 없는 숙명과 같
습니다. 이 절에서는
SQL
을 활용해 데이터 타입 변경하기, 날짜 또는 타임스탬프 값에서 필요
한 값만 추출하기, 특정 값에서 날짜 및 타임스탬프 값 생성하기 등 일반적으로 많이 사용하는
타입 변환을 알아봅니다. 먼저, 현재 날짜와 시간 데이터를 반환하는 간단한 함수를 살펴봅시다.
데이터를 분석할 때, 현재 날짜나 시간을 가져오는 일은 아주 흔합니다. 예를 들어, 데이터셋에
타임스탬프 값을 넣거나 여러 목적으로 날짜를 계산할 때 현재 날짜 또는 시간을 사용합니다.
현재 날짜와 시간은 데이터베이스가 동작하는 서버의 ‘시스템 시간’을 기준으로 결정되며
SQL
로 손쉽게 알아낼 수 있습니다. 사용 방법은 데이터베이스마다 조금씩 다릅니다.
몇몇 데이터베이스에서 제공하는 괄호 없는
current
_
date
함수는 현재 날짜를 ...
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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.