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MYSQL ์ฝ”๋”ฉํ…Œ์ŠคํŠธ์—ฐ์Šต: ์ด๋ฆ„์ด ์žˆ๋Š” ๋™๋ฌผ์˜ ์•„์ด๋”” ์ฝ”๋”ฉํ…Œ์ŠคํŠธ ์—ฐ์Šต - ์ด๋ฆ„์ด ์žˆ๋Š” ๋™๋ฌผ์˜ ์•„์ด๋”” ANIMAL_INS ํ…Œ์ด๋ธ”์€ ๋™๋ฌผ ๋ณดํ˜ธ์†Œ์— ๋“ค์–ด์˜จ ๋™๋ฌผ์˜ ์ •๋ณด๋ฅผ ๋‹ด์€ ํ…Œ์ด๋ธ”์ž…๋‹ˆ๋‹ค. ANIMAL_INS ํ…Œ์ด๋ธ” ๊ตฌ์กฐ๋Š” ๋‹ค์Œ๊ณผ ๊ฐ™์œผ๋ฉฐ, ANIMAL_ID, ANIMAL_TYPE, DATETIME, INTAKE_CONDITION, NAME, SEX_UPON_INTAKE๋Š” ๊ฐ๊ฐ ๋™๋ฌผ์˜ ์•„์ด๋”” programmers.co.kr ํ•ด๋‹น ๊ธ€์€ Programmers ์ฝ”๋”ฉํ…Œ์ŠคํŠธ ์—ฐ์Šต์„ ํ† ๋Œ€๋กœ MYSQL ๋กœ ์ž‘์„ฑ๋˜์—ˆ์Šต๋‹ˆ๋‹ค. Q ๋ฌธ์ œ: ์ด๋ฆ„์ด ์žˆ๋Š” ๋™๋ฌผ์˜ ์•„์ด๋”” A ๋ฌธ์ œํ’€์ด : -- ์ฝ”๋“œ๋ฅผ ์ž…๋ ฅํ•˜์„ธ์š” SELECT ANIMAL_ID FROM ANIMAL_INS WHERE NOT ISNULL(NAME) ํ•ด๋‹น๋ฌธ์ œ๋Š” ๋ฐ์ดํ„ฐ ๊ฒฐ์ธก๊ฐ’ (NULL)์„ ์ œ์™ธํ•œ ๊ฐ’๋“ค์„ ์ถœ๋ ฅํ•˜๋Š” ๋ฌธ์ œ์ž…๋‹ˆ๋‹ค. E: .. 2021. 1. 14.
MYSQL ์ฝ”๋”ฉํ…Œ์ŠคํŠธ์—ฐ์Šต: ์ž…์–‘ ์‹œ๊ฐ ๊ตฌํ•˜๊ธฐ (2) (์žฌ๊ท€์ฟผ๋ฆฌ) ์ฝ”๋”ฉํ…Œ์ŠคํŠธ ์—ฐ์Šต - ์ž…์–‘ ์‹œ๊ฐ ๊ตฌํ•˜๊ธฐ(2) ANIMAL_OUTS ํ…Œ์ด๋ธ”์€ ๋™๋ฌผ ๋ณดํ˜ธ์†Œ์—์„œ ์ž…์–‘ ๋ณด๋‚ธ ๋™๋ฌผ์˜ ์ •๋ณด๋ฅผ ๋‹ด์€ ํ…Œ์ด๋ธ”์ž…๋‹ˆ๋‹ค. ANIMAL_OUTS ํ…Œ์ด๋ธ” ๊ตฌ์กฐ๋Š” ๋‹ค์Œ๊ณผ ๊ฐ™์œผ๋ฉฐ, ANIMAL_ID, ANIMAL_TYPE, DATETIME, NAME, SEX_UPON_OUTCOME๋Š” ๊ฐ๊ฐ ๋™๋ฌผ์˜ ์•„์ด๋””, ์ƒ๋ฌผ programmers.co.kr ํ•ด๋‹น ๊ธ€์€ Programmers ์ฝ”๋”ฉํ…Œ์ŠคํŠธ ์—ฐ์Šต์„ ํ† ๋Œ€๋กœ MYSQL ๋กœ ์ž‘์„ฑ๋˜์—ˆ์Šต๋‹ˆ๋‹ค. Q ๋ฌธ์ œ: ์ž…์–‘ ์‹œ๊ฐ ๊ตฌํ•˜๊ธฐ (2) A ๋ฌธ์ œํ’€์ด : WITH RECURSIVE NEWTABLE AS ( SELECT 0 AS HOUR UNION ALL SELECT HOUR + 1 FROM NEWTABLE WHERE HOUR < 23 ) SELECT NEWTABLE.HOUR,.. 2021. 1. 13.
MYSQL ์ฝ”๋”ฉํ…Œ์ŠคํŠธ์—ฐ์Šต: ์ž…์–‘ ์‹œ๊ฐ ๊ตฌํ•˜๊ธฐ (1) ์ฝ”๋”ฉํ…Œ์ŠคํŠธ ์—ฐ์Šต - ์ž…์–‘ ์‹œ๊ฐ ๊ตฌํ•˜๊ธฐ(1) ANIMAL_OUTS ํ…Œ์ด๋ธ”์€ ๋™๋ฌผ ๋ณดํ˜ธ์†Œ์—์„œ ์ž…์–‘ ๋ณด๋‚ธ ๋™๋ฌผ์˜ ์ •๋ณด๋ฅผ ๋‹ด์€ ํ…Œ์ด๋ธ”์ž…๋‹ˆ๋‹ค. ANIMAL_OUTS ํ…Œ์ด๋ธ” ๊ตฌ์กฐ๋Š” ๋‹ค์Œ๊ณผ ๊ฐ™์œผ๋ฉฐ, ANIMAL_ID, ANIMAL_TYPE, DATETIME, NAME, SEX_UPON_OUTCOME๋Š” ๊ฐ๊ฐ ๋™๋ฌผ์˜ ์•„์ด๋””, ์ƒ๋ฌผ programmers.co.kr ํ•ด๋‹น ๊ธ€์€ Programmers ์ฝ”๋”ฉํ…Œ์ŠคํŠธ ์—ฐ์Šต์„ ํ† ๋Œ€๋กœ MYSQL ๋กœ ์ž‘์„ฑ๋˜์—ˆ์Šต๋‹ˆ๋‹ค. Q ๋ฌธ์ œ: ์ž…์–‘ ์‹œ๊ฐ ๊ตฌํ•˜๊ธฐ (1) A ๋ฌธ์ œํ’€์ด: -- ์ฝ”๋“œ๋ฅผ ์ž…๋ ฅํ•˜์„ธ์š” SELECT HOUR(DATETIME) AS HOUR, COUNT(HOUR(DATETIME)) AS COUNT FROM ANIMAL_OUTS GROUP BY HOUR HAVING HOUR BETWEEN .. 2021. 1. 11.
MYSQL ์ฝ”๋”ฉํ…Œ์ŠคํŠธ์—ฐ์Šต: ๋™๋ช… ๋™๋ฌผ์ˆ˜ ์ฐพ๊ธฐ (GROUP BY, HAVING) ์ฝ”๋”ฉํ…Œ์ŠคํŠธ ์—ฐ์Šต - ๋™๋ช… ๋™๋ฌผ ์ˆ˜ ์ฐพ๊ธฐ ANIMAL_INS ํ…Œ์ด๋ธ”์€ ๋™๋ฌผ ๋ณดํ˜ธ์†Œ์— ๋“ค์–ด์˜จ ๋™๋ฌผ์˜ ์ •๋ณด๋ฅผ ๋‹ด์€ ํ…Œ์ด๋ธ”์ž…๋‹ˆ๋‹ค. ANIMAL_INS ํ…Œ์ด๋ธ” ๊ตฌ์กฐ๋Š” ๋‹ค์Œ๊ณผ ๊ฐ™์œผ๋ฉฐ, ANIMAL_ID, ANIMAL_TYPE, DATETIME, INTAKE_CONDITION, NAME, SEX_UPON_INTAKE๋Š” ๊ฐ๊ฐ ๋™๋ฌผ์˜ ์•„์ด๋”” programmers.co.kr ํ•ด๋‹น ๊ธ€์€ Programmers ์ฝ”๋”ฉํ…Œ์ŠคํŠธ ์—ฐ์Šต์„ ํ† ๋Œ€๋กœ MYSQL ๋กœ ์ž‘์„ฑ๋˜์—ˆ์Šต๋‹ˆ๋‹ค. Q ๋ฌธ์ œ: ์ด๋ฆ„์ด ๊ฐ™์€ ๋ฐ์ดํ„ฐ ์ฐพ๊ธฐ A ๋ฌธ์ œํ’€์ด: -- ์ฝ”๋“œ๋ฅผ ์ž…๋ ฅํ•˜์„ธ์š” SELECT NAME, COUNT(NAME) FROM ANIMAL_INS GROUP BY NAME HAVING COUNT(NAME) > 1; ํ•ด๋‹น ๋ฌธ์ œ๋Š” ํŠน์ • ์นผ๋Ÿผ์— ํฌํ•จํ•˜๊ณ  ์žˆ๋Š” ์ค‘๋ณต๋ฐ์ดํ„ฐ์™€.. 2021. 1. 11.
MYSQL ์ฝ”๋”ฉํ…Œ์ŠคํŠธ์—ฐ์Šต: ์ƒ์œ„ N๊ฐœ ๋ ˆ์ฝ”๋“œ ์ถœ๋ ฅํ•˜๊ธฐ ( LIMIT ) ์ฝ”๋”ฉํ…Œ์ŠคํŠธ ์—ฐ์Šต - ์ƒ์œ„ n๊ฐœ ๋ ˆ์ฝ”๋“œ ANIMAL_INS ํ…Œ์ด๋ธ”์€ ๋™๋ฌผ ๋ณดํ˜ธ์†Œ์— ๋“ค์–ด์˜จ ๋™๋ฌผ์˜ ์ •๋ณด๋ฅผ ๋‹ด์€ ํ…Œ์ด๋ธ”์ž…๋‹ˆ๋‹ค. ANIMAL_INS ํ…Œ์ด๋ธ” ๊ตฌ์กฐ๋Š” ๋‹ค์Œ๊ณผ ๊ฐ™์œผ๋ฉฐ, ANIMAL_ID, ANIMAL_TYPE, DATETIME, INTAKE_CONDITION, NAME, SEX_UPON_INTAKE๋Š” ๊ฐ๊ฐ ๋™๋ฌผ์˜ ์•„์ด๋”” programmers.co.kr ํ•ด๋‹น ๊ธ€์€ Programmers ์ฝ”๋”ฉํ…Œ์ŠคํŠธ ์—ฐ์Šต์„ ํ† ๋Œ€๋กœ MYSQL ๋กœ ์ž‘์„ฑ๋˜์—ˆ์Šต๋‹ˆ๋‹ค. Q ๋ฌธ์ œ: ์ƒ์œ„ N๊ฐœ ๋ ˆ์ฝ”๋“œ ์ถœ๋ ฅํ•˜๊ธฐ A ๋ฌธ์ œํ’€์ด: -- ์ฝ”๋“œ๋ฅผ ์ž…๋ ฅํ•˜์„ธ์š” SELECT NAME FROM ANIMAL_INS ORDER BY DATETIME LIMIT 1 ํ•ด๋‹น ๋ฌธ์ œ๋Š” ์ •๋ ฌ ํ›„ ์ƒ์œ„ ํ•ญ๋ชฉ์˜ ๋ ˆ์ฝ”๋“œ๋ฅผ ์ถœ๋ ฅํ•  ์ˆ˜ ์žˆ๋Š”์ง€๋ฅผ ํ…Œ์ŠคํŠธํ•˜๋Š” ๋ฌธ์ œ์˜€์Šต๋‹ˆ๋‹ค. E: ๋ช….. 2021. 1. 10.
MYSQL ์ฝ”๋”ฉํ…Œ์ŠคํŠธ์—ฐ์Šต: ์—ฌ๋Ÿฌ ๊ธฐ์ค€์œผ๋กœ ์ •๋ ฌํ•˜๊ธฐ (ORDER BY) ์ฝ”๋”ฉํ…Œ์ŠคํŠธ ์—ฐ์Šต - ์—ฌ๋Ÿฌ ๊ธฐ์ค€์œผ๋กœ ์ •๋ ฌํ•˜๊ธฐ ANIMAL_INS ํ…Œ์ด๋ธ”์€ ๋™๋ฌผ ๋ณดํ˜ธ์†Œ์— ๋“ค์–ด์˜จ ๋™๋ฌผ์˜ ์ •๋ณด๋ฅผ ๋‹ด์€ ํ…Œ์ด๋ธ”์ž…๋‹ˆ๋‹ค. ANIMAL_INS ํ…Œ์ด๋ธ” ๊ตฌ์กฐ๋Š” ๋‹ค์Œ๊ณผ ๊ฐ™์œผ๋ฉฐ, ANIMAL_ID, ANIMAL_TYPE, DATETIME, INTAKE_CONDITION, NAME, SEX_UPON_INTAKE๋Š” ๊ฐ๊ฐ ๋™๋ฌผ์˜ ์•„์ด๋”” programmers.co.kr ํ•ด๋‹น ๊ธ€์€ Programmers ์ฝ”๋”ฉํ…Œ์ŠคํŠธ ์—ฐ์Šต์„ ํ† ๋Œ€๋กœ MYSQL ๋กœ ์ž‘์„ฑ๋˜์—ˆ์Šต๋‹ˆ๋‹ค. Q ๋ฌธ์ œ: ์—ฌ๋Ÿฌ ๊ธฐ์ค€์œผ๋กœ ์ •๋ ฌํ•˜๊ธฐ A ๋ฌธ์ œํ’€์ด: -- ์ฝ”๋“œ๋ฅผ ์ž…๋ ฅํ•˜์„ธ์š” SELECT ANIMAL_ID, NAME, DATETIME FROM ANIMAL_INS ORDER BY NAME ASC, DATETIME DESC ํ•ด๋‹น ๋ฌธ์ œ๋Š” ๋‘๊ฐ€์ง€ ์กฐ๊ฑด์œผ๋กœ ์ •๋ ฌํ•˜์—ฌ ํ…Œ์ด๋ธ”.. 2021. 1. 10.
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