SELECT o.animal_id, o.name
FROM animal_outs o left outer join animal_ins i
ON o.animal_id = i.animal_id
WHERE i.datetime IS NULL
ORDER BY o.animal_id
SELECT i.animal_id, i.name
FROM animal_ins i INNER JOIN animal_outs o
ON i.animal_id = o.animal_id
WHERE o.datetime <= i.datetime
ORDER BY i.datetime;
SELECT i.name, i.datetime
FROM animal_ins i LEFT OUTER JOIN animal_outs o
ON i.animal_id = o.animal_id
WHERE o.animal_id IS NULL
ORDER BY i.datetime
LIMIT 3
마지막으로 id순으로 정렬
정답 쿼리 - 내가 푼
SELECT i.animal_id, i.animal_type, i.name
FROM animal_ins i JOIN animal_outs o
ON i.animal_id = o.animal_id
WHERE i.sex_upon_intake like 'Intact%'
AND o.sex_upon_outcome not like 'Intact%'
ORDER BY i.animal_id
SELECT I.ANIMAL_ID, I.ANIMAL_TYPE, I.NAME
FROM ANIMAL_INS as I JOIN ANIMAL_OUTS as O
WHERE I.ANIMAL_ID = O.ANIMAL_ID
AND I.SEX_UPON_INTAKE != O.SEX_UPON_OUTCOME
ORDER BY I.ANIMAL_ID;