[Level 3] 오랜 기간 보호한 동물(1)

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