What cities have more than 3 airports in the United States?
select city from airports where country = 'United States' group by city having count ( * ) > 3
What cities in the United States have more than 4 airports?
select city from airports where country = 'United States' group by city having count ( * ) > 4
What are their names?
select name from airports where country = 'United States' group by city having count ( * ) > 4
Show the names of all airports with elevation over 4000.
select name from airports where elevation > 4000
Show the names of all airports with elevation over 5000.
select name from airports where elevation > 5000