What are the different pilot names who had piloted a flight in the country 'United States' or in the airport named 'Billund Airport'?
create table airport (id varchar, country varchar, name varchar, PRIMARY KEY (id)); create table flight (pilot varchar, airport_id varchar, PRIMARY KEY (pilot))
select distinct t2.pilot from airport as t1 join flight as t2 on t1.id = t2.airport_id where t1.country = 'united states' or t1.name = 'billund airport'