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[programmers] JOIN๋ฌธ - SQL ๊ณ ๋“์  Kit

๋ฟŒ์•ผ._. 2022. 2. 6. 00:38

์ฒ˜์Œ JOIN๋ฌธ์„ ์ ‘ํ–ˆ์„ ๋•Œ ์–ด๋–ป๊ฒŒ ํ’€์–ด์•ผ ํ• ์ง€ ๋ชฐ๋ผ ์ฐพ์•„๋ดค์—ˆ๋‹ค.

JOIN๋ฌธ์„ ์‚ฌ์šฉํ•˜๋Š” ๋ฐฉ๋ฒ•์„ ์ฐพ์•„๋ณธ ํ›„ ๋ฌธ์ œ์— ์ ์šฉํ•˜์—ฌ ํ•ด๊ฒฐํ•  ์ˆ˜ ์žˆ์—ˆ๋‹ค.

 

์ด๋ ‡๊ฒŒ ํ‘ธ๋Š” ๊ฒƒ์ธ์ง€ ๋งž๋Š”์ง€ ๋ชจ๋ฅด๊ฒ ์ง€๋งŒ 4๋ฌธ์ œ๋ฅผ ํ†ต๊ณผํ•  ์ˆ˜ ์žˆ์—ˆ๋‹ค.

 

 

๋ถ€์กฑํ•˜์ง€๋งŒ ์•„์ฃผ ๊ฐ„๋‹จํ•˜๊ฒŒ JOIN์— ๋Œ€ํ•ด ์ •๋ฆฌํ•ด๋ณด์ž!

https://melody-coding.tistory.com/199

 

JOIN

โ“JOIN SELECT A.๋ณ€์ˆ˜, A.๋ณ€์ˆ˜ from A JOIN B ON A.๋ณ€์ˆ˜ = B.๋ณ€์ˆ˜ WHERE B.๋ณ€์ˆ˜ ~~ โ“LEFT JOIN SELECT A.๋ณ€์ˆ˜, A.๋ณ€์ˆ˜ from A LEFT JOIN B ON A.๋ณ€์ˆ˜ = B.๋ณ€์ˆ˜ WHERE B.๋ณ€์ˆ˜ ~~~ JOIN๊ณผ LEFT JOIN ๋“ฑ ์ข…๋ฅ˜๊ฐ€ ๋‹ค์–‘..

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