코딩테스트 연습GROUP BY입양 시각 구하기(1)

https://school.programmers.co.kr/learn/courses/30/lessons/59412

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정답1

SELECT 
HOUR(DATETIME)AS HOUR,

COUNT(*) AS COUNT 
FROM ANIMAL_OUTS
GROUP BY 1
HAVING HOUR BETWEEN 9 AND 19
ORDER BY 1

 

정답2

SELECT DATE_FORMAT(DATETIME, '%H') AS HOUR, 
       COUNT(DATE_FORMAT(DATETIME, '%H')) AS COUNT
FROM ANIMAL_OUTS
GROUP BY HOUR
HAVING HOUR BETWEEN 9 AND 19
ORDER BY HOUR ASC