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Problem Solving/SQL

[ํ”„๋กœ๊ทธ๋ž˜๋จธ์Šค] MYSQL - String, Date

by DevIseo 2022. 7. 25.

[ํ”„๋กœ๊ทธ๋ž˜๋จธ์Šค] MYSQL - String, Date

1. ๋ฃจ์‹œ์™€ ์—˜๋ผ ์ฐพ๊ธฐ

https://school.programmers.co.kr/learn/courses/30/lessons/59046

 

ํ”„๋กœ๊ทธ๋ž˜๋จธ์Šค

์ฝ”๋“œ ์ค‘์‹ฌ์˜ ๊ฐœ๋ฐœ์ž ์ฑ„์šฉ. ์Šคํƒ ๊ธฐ๋ฐ˜์˜ ํฌ์ง€์…˜ ๋งค์นญ. ํ”„๋กœ๊ทธ๋ž˜๋จธ์Šค์˜ ๊ฐœ๋ฐœ์ž ๋งž์ถคํ˜• ํ”„๋กœํ•„์„ ๋“ฑ๋กํ•˜๊ณ , ๋‚˜์™€ ๊ธฐ์ˆ  ๊ถํ•ฉ์ด ์ž˜ ๋งž๋Š” ๊ธฐ์—…๋“ค์„ ๋งค์นญ ๋ฐ›์œผ์„ธ์š”.

programmers.co.kr

-- ์ฝ”๋“œ๋ฅผ ์ž…๋ ฅํ•˜์„ธ์š”
SELECT ANIMAL_ID, NAME, SEX_UPON_INTAKE
FROM ANIMAL_INS
WHERE NAME IN ('Lucy','Ella','Pickle','Rogan','Sabrina','Mitty');

 

2. ์ด๋ฆ„์— el์ด ๋“ค์–ด๊ฐ€๋Š” ๋™๋ฌผ ์ฐพ๊ธฐ

https://school.programmers.co.kr/learn/courses/30/lessons/59047

 

ํ”„๋กœ๊ทธ๋ž˜๋จธ์Šค

์ฝ”๋“œ ์ค‘์‹ฌ์˜ ๊ฐœ๋ฐœ์ž ์ฑ„์šฉ. ์Šคํƒ ๊ธฐ๋ฐ˜์˜ ํฌ์ง€์…˜ ๋งค์นญ. ํ”„๋กœ๊ทธ๋ž˜๋จธ์Šค์˜ ๊ฐœ๋ฐœ์ž ๋งž์ถคํ˜• ํ”„๋กœํ•„์„ ๋“ฑ๋กํ•˜๊ณ , ๋‚˜์™€ ๊ธฐ์ˆ  ๊ถํ•ฉ์ด ์ž˜ ๋งž๋Š” ๊ธฐ์—…๋“ค์„ ๋งค์นญ ๋ฐ›์œผ์„ธ์š”.

programmers.co.kr

-- ์ฝ”๋“œ๋ฅผ ์ž…๋ ฅํ•˜์„ธ์š”
SELECT ANIMAL_ID, NAME
FROM ANIMAL_INS
WHERE ANIMAL_TYPE = 'Dog' AND NAME LIKE '%EL%'
ORDER BY NAME

 

3. ์ค‘์„ฑํ™” ์—ฌ๋ถ€ ํŒŒ์•…ํ•˜๊ธฐ

https://school.programmers.co.kr/learn/courses/30/lessons/59409

 

ํ”„๋กœ๊ทธ๋ž˜๋จธ์Šค

์ฝ”๋“œ ์ค‘์‹ฌ์˜ ๊ฐœ๋ฐœ์ž ์ฑ„์šฉ. ์Šคํƒ ๊ธฐ๋ฐ˜์˜ ํฌ์ง€์…˜ ๋งค์นญ. ํ”„๋กœ๊ทธ๋ž˜๋จธ์Šค์˜ ๊ฐœ๋ฐœ์ž ๋งž์ถคํ˜• ํ”„๋กœํ•„์„ ๋“ฑ๋กํ•˜๊ณ , ๋‚˜์™€ ๊ธฐ์ˆ  ๊ถํ•ฉ์ด ์ž˜ ๋งž๋Š” ๊ธฐ์—…๋“ค์„ ๋งค์นญ ๋ฐ›์œผ์„ธ์š”.

programmers.co.kr

-- ์ฝ”๋“œ๋ฅผ ์ž…๋ ฅํ•˜์„ธ์š”
SELECT ANIMAL_ID, NAME,
CASE WHEN SEX_UPON_INTAKE LIKE "%NE%" OR SEX_UPON_INTAKE 
LIKE "SP%" THEN 'O' ELSE 'X' END AS "์ค‘์„ฑํ™”" 
FROM ANIMAL_INS

 

4. ์˜ค๋žœ ๊ธฐ๊ฐ„ ๋ณดํ˜ธํ•œ ๋™๋ฌผ(2)

https://school.programmers.co.kr/learn/courses/30/lessons/59411

 

ํ”„๋กœ๊ทธ๋ž˜๋จธ์Šค

์ฝ”๋“œ ์ค‘์‹ฌ์˜ ๊ฐœ๋ฐœ์ž ์ฑ„์šฉ. ์Šคํƒ ๊ธฐ๋ฐ˜์˜ ํฌ์ง€์…˜ ๋งค์นญ. ํ”„๋กœ๊ทธ๋ž˜๋จธ์Šค์˜ ๊ฐœ๋ฐœ์ž ๋งž์ถคํ˜• ํ”„๋กœํ•„์„ ๋“ฑ๋กํ•˜๊ณ , ๋‚˜์™€ ๊ธฐ์ˆ  ๊ถํ•ฉ์ด ์ž˜ ๋งž๋Š” ๊ธฐ์—…๋“ค์„ ๋งค์นญ ๋ฐ›์œผ์„ธ์š”.

programmers.co.kr

-- ์ฝ”๋“œ๋ฅผ ์ž…๋ ฅํ•˜์„ธ์š”
SELECT A.ANIMAL_ID, A.NAME
FROM ANIMAL_INS AS A, ANIMAL_OUTS AS B
WHERE A.ANIMAL_ID = B.ANIMAL_ID
ORDER BY B.DATETIME - A.DATETIME DESC
LIMIT 2

 

5. DATETIME์—์„œ DATE๋กœ ํ˜• ๋ณ€ํ™˜

https://school.programmers.co.kr/learn/courses/30/lessons/59414

 

ํ”„๋กœ๊ทธ๋ž˜๋จธ์Šค

์ฝ”๋“œ ์ค‘์‹ฌ์˜ ๊ฐœ๋ฐœ์ž ์ฑ„์šฉ. ์Šคํƒ ๊ธฐ๋ฐ˜์˜ ํฌ์ง€์…˜ ๋งค์นญ. ํ”„๋กœ๊ทธ๋ž˜๋จธ์Šค์˜ ๊ฐœ๋ฐœ์ž ๋งž์ถคํ˜• ํ”„๋กœํ•„์„ ๋“ฑ๋กํ•˜๊ณ , ๋‚˜์™€ ๊ธฐ์ˆ  ๊ถํ•ฉ์ด ์ž˜ ๋งž๋Š” ๊ธฐ์—…๋“ค์„ ๋งค์นญ ๋ฐ›์œผ์„ธ์š”.

programmers.co.kr

-- ์ฝ”๋“œ๋ฅผ ์ž…๋ ฅํ•˜์„ธ์š”

SELECT ANIMAL_ID, NAME, DATE_FORMAT(DATETIME, '%Y-%m-%d') AS "๋‚ ์งœ" 
FROM ANIMAL_INS

๋Œ“๊ธ€