Show the names of the buildings that have more than one company offices.
create table buildings (name varchar, id varchar, PRIMARY KEY (name)); create table companies (id varchar, PRIMARY KEY (id)); create table office_locations (building_id varchar, company_id varchar, PRIMARY KEY (building_id))
select t2.name from office_locations as t1 join buildings as t2 on t1.building_id = t2.id join companies as t3 on t1.company_id = t3.id group by t1.building_id having count(*) > 1