[SQL문제풀기] Number Of Units Per Nationality

문제

StrataScratch - Number Of Units Per Nationality

StrataScratch

https://platform.stratascratch.com/coding/10156-number-of-units-per-nationality?code_type=1

내가 작성한 정답

MySQL, PostgreSQL, Oracle

select h.nationality, count(distinct unit_id) apartment_count
from airbnb_hosts h
join airbnb_units u
on h.host_id = u.host_id
where h.age < 30 
    and u.unit_type = 'Apartment'
group by h.nationality
order by 2 desc;