[프로그래머스.SQL] SUM, MAX, MIN

가격이 비싼 식품의 정보 출력하기

# ORDER BY 사용
SELECT PRODUCT_ID, PRODUCT_NAME, PRODUCT_CD, CATEGORY, PRICE
FROM FOOD_PRODUCT
ORDER BY PRICE DESC LIMIT 1;

# MAX 사용
SELECT *
FROM FOOD_PRODUCT
WHERE PRICE = (SELECT MAX(PRICE) FROM FOOD_PRODUCT);

# FETCH FIRST N ROWS ONLY 사용
SELECT *
FROM FOOD_PRODUCT
ORDER BY PRICE DESC
FETCH FIRST 1 ROWS ONLY;

 

가장 비싼 상품 구하기

# ORDER BY, limit
SELECT PRICE AS MAX_PRICE
FROM PRODUCT
ORDER BY PRICE DESC limit 1;

# WHERE
SELECT PRICE AS MAX_PRICE
FROM PRODUCT
WHERE PRICE = (SELECT MAX(PRICE) FROM PRODUCT);

# MAX
SELECT MAX(PRICE) AS MAX_PRICE
FROM PRODUCT;

 

최대값 구하기

# ORDER BY 사용
SELECT DATETIME AS 시간
FROM ANIMAL_INS
ORDER BY DATETIME DESC limit 1;

# MAX 사용
SELECT MAX(DATETIME) AS 시간
FROM ANIMAL_INS;

 

최솟값 구하기

SELECT MIN(DATETIME) AS 시간
FROM ANIMAL_INS;

 

동물 수 구하기

SELECT COUNT(*) as count
FROM ANIMAL_INS;

SELECT COUNT(ANIMAL_ID) as count
FROM ANIMAL_INS;

 

 

중복 제거하기

SELECT COUNT(DISTINCT(NAME))
FROM ANIMAL_INS
# WHERE NAME IS NOT NULL
# COUNT(컬럼명)은 NULL 제외하고 카운트함