IS NULL - 프로그래머스 SQL 고득점 kit

IS NULL 값이 없음을 의미

IFNULL( ~~, '  ') AS ~~ 값이 NULL인 경우 다르게 표시하고 싶을 때 사용

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SELECT ANIMAL_ID FROM ANIMAL_INS WHERE NAME IS NULL ORDER BY ANIMAL_ID;

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

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