What are the hometowns that are shared by at least two gymnasts?
create table gymnast (gymnast_id varchar, PRIMARY KEY (gymnast_id)); create table people (hometown varchar, people_id varchar, PRIMARY KEY (hometown))
select t2.hometown from gymnast as t1 join people as t2 on t1.gymnast_id = t2.people_id group by t2.hometown having count(*) >= 2