CREATE TABLE lives_in (stuid DECIMAL, dormid DECIMAL, room_number DECIMAL)
CREATE TABLE has_amenity (dormid DECIMAL, amenid DECIMAL)
CREATE TABLE student (stuid DECIMAL, lname TEXT, fname TEXT, age DECIMAL, sex TEXT, major DECIMAL, advisor DECIMAL, city_code TEXT)
CREATE TABLE dorm (dormid DECIMAL, dorm_name TEXT, student_capacity DECIMAL, gender TEXT)
CREATE TABLE dorm_amenity (amenid DECIMAL, amenity_name TEXT)

Find the number of dorms that have some amenity.
SELECT COUNT(DISTINCT dormid) FROM has_amenity
SELECT COUNT(DISTINCT "dormid") FROM "has_amenity"