프로그래머스 SQL JOIN

없어진 기록 찾기

select outs.animal_id as ANIMAL_ID, outs.name as NAME
from ANIMAL_OUTS as outs
left outer join ANIMAL_INS as ins
on outs.animal_id = ins.animal_id
where ins.animal_id is null

있었는데요 없었습니다.

select ANIMAL_INS.animal_id, ANIMAL_INS.name
from ANIMAL_INS
inner join ANIMAL_OUTS AO
    on ANIMAL_INS.animal_id = AO.animal_id and ANIMAL_INS.datetime > AO.datetime
order by ANIMAL_INS.datetime

오랜 기간 보호한 동물(1)

select ANIMAL_INS.name as NAME, ANIMAL_INS.datetime as DATETIME
from ANIMAL_INS
left outer join ANIMAL_OUTS AO on ANIMAL_INS.animal_id = AO.animal_id
where AO.animal_id is null
order by ANIMAL_INS.datetime
limit 3

보호소에서 중성화한 동물

select ANIMAL_INS.ANIMAL_ID, ANIMAL_INS.ANIMAL_TYPE, ANIMAL_INS.NAME
from ANIMAL_INS
inner join ANIMAL_OUTS AO
    on ANIMAL_INS.animal_id = AO.animal_id and sex_upon_intake != AO.sex_upon_outcome
order by ANIMAL_INS.animal_id