How many branches are there?
select count(*) from branch
What about opened in 2011 or located at London?
select count(*) from branch where open_year = 2011 or city = 'London'
Show me the amount of memberships for them.
select membership_amount from branch where open_year = 2011 or city = 'London'
What are the minimum and maximum among them?
select min(membership_amount), max(membership_amount) from branch where open_year = 2011 or city = 'London'