[프로그래머스] NULL 처리하기 MySQL

출처: 프로그래머스

https://programmers.co.kr/learn/courses/30/lessons/59410

코딩테스트 연습 - NULL 처리하기

1. IF 문

SELECT ANIMAL_TYPE, 
	IF(NAME IS NULL,'No name',NAME) AS NAME,
	SEX_UPON_INTAKE
FROM ANIMAL_INS
ORDER BY ANIMAL_ID;

2. IFNULL() 

SELECT ANIMAL_TYPE, 
	IFNULL(NAME,'No name') AS NAME,
	SEX_UPON_INTAKE
FROM ANIMAL_INS
ORDER BY ANIMAL_ID;

3. CASE 문

SELECT ANIMAL_TYPE, 
	CASE
    	WHEN NAME IS NULL THEN 'No name'
    	ELSE NAME
	END AS NAME,
	SEX_UPON_INTAKE
FROM ANIMAL_INS
ORDER BY ANIMAL_ID;