[GROUP BY/LEVEL2] 입양 시각 구하기(1) (MySQL/Oracle)

MySQL

SELECT HOUR(DATETIME)
, COUNT(*) AS COUNT
FROM ANIMAL_OUTS
WHERE HOUR(DATETIME) >= 9
 AND HOUR(DATETIME) < 20
GROUP BY HOUR(DATETIME)
ORDER BY HOUR(DATETIME)

 

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Oracle

SELECT CASE
       WHEN TO_CHAR(DATETIME,'HH24') LIKE '0%'THEN SUBSTR(TO_CHAR(DATETIME,'HH24'),2,2)
       ELSE TO_CHAR(DATETIME,'HH24')
       END AS HOUR
     , COUNT(DATETIME)
  FROM ANIMAL_OUTS
 GROUP BY TO_CHAR(DATETIME,'HH24')
 HAVING TO_CHAR(DATETIME,'HH24') BETWEEN '09' AND '19'
ORDER BY TO_CHAR(DATETIME,'HH24')