What are the information of all the people?
select * from people
What are the birth places of all the people?
select birth_place from people
How many people in each of the birth place?
select birth_place, count(*) from people group by birth_place
What are the four most popular birth places?
select birth_place from people group by birth_place order by count(*) desc limit 4
What about top one?
select birth_place from people group by birth_place order by count(*) desc limit 1