How many buildings have height abouve average?
select count(*) from building where height_feet > (select avg(height_feet) from building)
What about floors above average?
select count(*) from building where height_feet > (select avg(floors) from building)
Give the union of the above.
select count(*) from building where height_feet > (select avg(height_feet) from building) or floors > (select avg(floors) from building)