[SQL] 프로그래머스

👀문제

1. 최댓값 구하기

2. 최솟값 구하기

3. 동물 수 구하기

4. 중복 제거하기

5. 고양이와 개는 몇마리 있을까

6. 동명 동물 수 찾기

---

💡답

-- MAX
SELECT MAX(DATETIME) AS '시간'
FROM ANIMAL_INS

-- MIN
SELECT MIN(DATETIME) AS '시간'
FROM ANIMAL_INS

-- COUNT
SELECT COUNT(ANIMAL_ID) AS 'COUNT'
FROM ANIMAL_INS

-- COUNT DISTINCT
SELECT COUNT(DISTINCT NAME)
FROM ANIMAL_INS

-- COUNT ORDERBY
SELECT ANIMAL_TYPE, COUNT(ANIMAL_TYPE) AS COUNT
FROM ANIMAL_INS
GROUP BY ANIMAL_TYPE
ORDER BY
CASE ANIMAL_TYPE
	WHEN 'Cat' THEN 1
	WHEN 'Dog' THEN 2
	ELSE 3
END

-- COUNT GROUP BY HAVING ORDER BY
SELECT NAME, COUNT(*) AS COUNT
FROM ANIMAL_INS
GROUP BY NAME
HAVING COUNT(NAME) >= 2
ORDER BY NAME

---

📜해석

MAX

MIN

COUNT

COUNT + DISTINCT

COUNT + ORDERBY

COUNT + GROUP BY + HAVING + ORDER BY