[프로그래머스]오랜 기간 보호한 동물(1) (MySQL) JOIN

-- # SELECT AI.NAME, AI.DATETIME
--     # FROM ANIMAL_INS AI LEFT JOIN ANIMAL_OUTS AO
--       # ON AI.ANIMAL_ID = AO.ANIMAL_ID
--       # WHERE AO.ANIMAL_ID IS NULL
--       # ORDER BY AI.DATETIME LIMIT 3;

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