SQL - WITH RECURSIVE

with recursive 뷰명 as (
    초기 SQL

    union all(or union)

    반복할 SQL(+반복을 멈출 where절 포함)

)
select * from 뷰명;

 

WITH RECURSIVE TIME AS(
SELECT 0 AS h
    UNION all
    SELECT h+1 FROM TIME WHERE h < 23)

SELECT h, count(HOUR(DATETIME)) AS 'COUNT'
FROM TIME left OUTER JOIN ANIMAL_OUTS
ON (h=HOUR(DATETIME))
GROUP BY h