59413.md

프로그래머스 59413

'입양 시각 구하기(2)'

🔗 https://school.programmers.co.kr/learn/courses/30/lessons/59413

WITH RECURSIVE NUM AS (
    SELECT 0 AS HOUR

    UNION ALL

    SELECT HOUR + 1 FROM NUM
    WHERE HOUR < 23
    )

SELECT
    n.HOUR,
    COALESCE(t.DATE_COUNT,0) AS COUNT
FROM 
    NUM n
    LEFT JOIN (
        SELECT HOUR(DATETIME) AS HOUR, COUNT(*) DATE_COUNT
        FROM ANIMAL_OUTS
        GROUP BY HOUR(DATETIME)) t
    ON n.HOUR = t.HOUR
ORDER BY
    HOUR ASC;