GROUP BY 1
[SQL] GROUP BY ์ ˆ

1. GROUP BY ์ ˆ - ๊ทธ๋ฃนํ™” : ์—ฌ๋Ÿฌ ๋ฐ์ดํ„ฐ์—์„œ ์˜๋ฏธ ์žˆ๋Š” ํ•˜๋‚˜์˜ ๊ฒฐ๊ณผ๋ฅผ ํŠน์ • ์นผ๋Ÿผ ๊ฐ’ ๋ณ„๋กœ ๋ฌถ์–ด์„œ ์ถœ๋ ฅ ex) DEPTNO๊ฐ€ 10์ผ ๋•Œ, 20์ผ ๋•Œ, 30์ผ ๋•Œ ๊ธ‰์—ฌ์˜ ํ‰๊ท ๊ฐ’์„ ๊ตฌํ•˜๊ณ  ์‹ถ์„ ๋•Œ ํ•˜๋‚˜์”ฉ SQL๋ฌธ์„ ์ž‘์„ฑํ•ด์•ผํ•˜์ง€๋งŒ GROUP BY ์ ˆ์„ ์‚ฌ์šฉํ•˜๋ฉด DEPTNO ๋ณ„๋กœ ๋ฌถ์–ด์„œ ํ‰๊ท ๊ฐ’์„ ํ•œ๋ฒˆ์— ๊ณ„์‚ฐํ•  ์ˆ˜ ์žˆ๋‹ค SELECT [์กฐํšŒํ•  ์นผ๋Ÿผ 1 ์ด๋ฆ„], [์นผ๋Ÿผ 2 ์ด๋ฆ„], … , [์นผ๋Ÿผ N ์ด๋ฆ„] FROM [์กฐํšŒํ•  ํ…Œ์ด๋ธ” ์ด๋ฆ„] WHERE[์กฐํšŒํ•  ์นผ๋Ÿผ์„ ์„ ๋ณ„ํ•˜๊ธฐ ์œ„ํ•œ ์กฐ๊ฑด์‹] GROUP BY[๊ทธ๋ฃนํ™”ํ•  ์นผ๋Ÿผ์„ ์ง€์ •(์—ฌ๋Ÿฌ๊ฐœ ๊ฐ€๋Šฅ)] ORDER BY[์ •๋ ฌํ•˜๋ ค๋Š” ์นผ๋Ÿผ ์ง€์ •] [์ •๋ ฌ ์˜ต์…˜]; -- 1. DEPTNO ๋ณ„๋กœ ๊ทธ๋ฃนํ™” SELECTAVG(SAL), DEPTNO FROMEMP GROUP BYDEPTNO..
ํ”„๋กœ๊ทธ๋ž˜๋ฐ ์–ธ์–ด/DataBase 2021.03.03
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