SQL. 있었는데요 없었습니다

https://programmers.co.kr/learn/courses/30/lessons/59043

단순한 JOIN 문제이다.

SELECT INS.ANIMAL_ID, INS.NAME
FROM ANIMAL_INS INS
JOIN ANIMAL_OUTS OUTS
ON INS.ANIMAL_ID = OUTS.ANIMAL_ID
WHERE OUTS.DATETIME < INS.DATETIME
ORDER BY INS.DATETIME