[JOIN] 오랜 기간 보호한 동물(1)

문제 설명

 

예시

 

해결

SELECT NAME, DATETIME
FROM ANIMAL_INS
WHERE ANIMAL_ID NOT IN (SELECT ANIMAL_ID FROM ANIMAL_OUTS)
ORDER BY DATETIME 
LIMIT 3;

SELECT A.NAME, A.DATETIME
FROM ANIMAL_INS A
LEFT JOIN ANIMAL_OUTS B 
ON A.ANIMAL_ID = B.ANIMAL_ID
WHERE B.ANIMAL_ID IS NULL
ORDER BY A.DATETIME
LIMIT 3;