Du kan bruge aggregering og tælle departure_airport
:
select v.airline
from volo v
group by v.airline
having count(distinct departure_airport) = (select count(*) from airport);
Du kan bruge aggregering og tælle departure_airport
:
select v.airline
from volo v
group by v.airline
having count(distinct departure_airport) = (select count(*) from airport);