[programmers]SQL_GROUPBY
💯 solving-algo | March 14, 2021
고양이와 개는 몇 마리 있을까
SELECT ANIMAL_TYPE, COUNT(ANIMAL_ID) AS 'count'
FROM ANIMAL_INS
GROUP BY ANIMAL_TYPE
ORDER BY ANIMAL_TYPE동명 동물 수 찾기
SELECT NAME, COUNT(NAME) AS COUNT
FROM ANIMAL_INS
GROUP BY NAME
HAVING COUNT(NAME) >=2
ORDER BY NAME입양 시각 구하기(1)
SELECT HOUR(DATETIME) as HOUR, COUNT(ANIMAL_ID) as COUNT
FROM ANIMAL_OUTS
GROUP BY HOUR(DATETIME)
HAVING HOUR >= 9 and HOUR <= 19
ORDER BY HOUR입양 시각 구하기(2)
SET @hour := -1; -- 변수 선언
SELECT (@hour := @hour + 1) as HOUR,
(SELECT COUNT(*) FROM ANIMAL_OUTS WHERE HOUR(DATETIME) = @hour) as COUNT
FROM ANIMAL_OUTS
WHERE @hour < 23