Find the name of amenity that is most common in all dorms.
create table dorm_amenity (amenity_name varchar, amenid varchar, PRIMARY KEY (amenity_name)); create table has_amenity (amenid varchar, PRIMARY KEY (amenid))
select t1.amenity_name from dorm_amenity as t1 join has_amenity as t2 on t1.amenid = t2.amenid group by t2.amenid order by count(*) desc limit 1