List all the  pilot positions.
select position from pilot
Keep the ones whose age is younger than 35
select position from pilot where age < 35
What about the join year is early than 2000?
select position from pilot where join_year < 2000
What about in the range of year f2000 and 2005?
select position from pilot where join_year < 2000 intersect select position from pilot where join_year > 2005