Computer Science/Database
[SQL/MySQL] 시간대별 통계 내기
단순하게 데이터 범위 내에서 시간대별 통계 내기 SELECT HOUR(DATETIME) HOUR, COUNT(ANIMAL_ID) COUNT FROM ANIMAL_OUTS GROUP BY HOUR ORDER BY HOUR; 모든 시간대별 통계내기 재귀적 쿼리(with recursive)와 left outer join을 사용한다. WITH RECURSIVE temp as ( (SELECT 0 HOUR) union (SELECT HOUR+1 FROM temp where HOUR < 23) ) SELECT temp.HOUR, IFNULL(A.COUNT, 0) COUNT FROM temp LEFT OUTER JOIN ( SELECT HOUR(DATETIME) HOUR, COUNT(*) COUNT FROM ANIM..