[SQL_IS NULL]

📌NULL 처리하기

SELECT ANIMAL_TYPE,IFNULL(NAME,"No name"),SEX_UPON_INTAKE 
FROM ANIMAL_INS 
ORDER BY ANIMAL_ID

#다른 풀이
SELECT ANIMAL_TYPE,
    CASE
        WHEN NAME IS NULL THEN "No name"
        ELSE NAME
    END as NAME, SEX_UPON_INTAKE
FROM ANIMAL_INS

📌이름이 있는 동물의 아이디

SELECT ANIMAL_ID FROM ANIMAL_INS 
WHERE NAME IS NOT NULL 
ORDER BY ANIMAL_ID

📌나이 정보가 없는 회원 수 구하기

SELECT COUNT(*) AS USERS 
FROM USER_INFO 
WHERE AGE IS NULL

📌경기도에 위치한 식품창고 목록 출력하기

SELECT WAREHOUSE_ID, WAREHOUSE_NAME, ADDRESS,IFNULL(FREEZER_YN,"N") AS FREEZER_YN
FROM FOOD_WAREHOUSE
WHERE ADDRESS LIKE '경기도%'
ORDER BY WAREHOUSE_ID