[programmers] MySQL - Lv.3 오랜 기간 보호한 동물 (1) (join)

문제

 

 

 

 

 

풀이

 

SELECT a.name, a.datetime
from animal_ins as a left join animal_outs as b
    on a.animal_id = b.animal_id
where b.animal_id is null
order by a.datetime
limit 3;