What are the names of all the people?
select name from people
Show the names of body builders.
select t2.name from body_builder as t1 join people as t2 on t1.people_id = t2.people_id
Show the names of them which has the greatest body weight.
select t2.name from body_builder as t1 join people as t2 on t1.people_id = t2.people_id order by t2.weight desc limit 1