What are the average score and average staff number of all shops?
select avg ( num_of_staff ), avg ( score ) from shop
Which shop has the highest score?
select * from shop order by score desc limit 1
How many shops have more staff than shop 10?
select count ( * ) from shop where num_of_staff > ( select num_of_staff from shop where shop_id = 10 )
The street shop 10 is on.
select * from shop where address = ( select address from shop where shop_id = 10 ) and shop_id ! = 10