[프로그래머스] [SQL] 입양 시각 구하기(2)

문제 설명

문제 풀이

SET @hour = -1;

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

실행 결과