[프로그래머스/MySQL] 입양 시각 구하기(2)

 

 

나의 풀이

SET @TIME := -1;

SELECT  (@TIME := @TIME + 1)            AS 'HOUR',
        (SELECT COUNT(DATETIME)
         FROM ANIMAL_OUTS
         WHERE HOUR(DATETIME) = @TIME)  AS 'COUNT'
FROM ANIMAL_OUTS
WHERE @TIME < 23