CREATE TABLE station (station_id DECIMAL, name TEXT, annual_entry_exit DECIMAL, annual_interchanges DECIMAL, total_passengers DECIMAL, location TEXT, main_services TEXT, number_of_platforms DECIMAL)
CREATE TABLE train_station (train_id DECIMAL, station_id DECIMAL)
CREATE TABLE train (train_id DECIMAL, name TEXT, time TEXT, service TEXT)

Show all locations which don't have a train station with at least 15 platforms.
SELECT location FROM station EXCEPT SELECT location FROM station WHERE number_of_platforms >= 15
SELECT "location" FROM "station" EXCEPT SELECT "location" FROM "station" WHERE "number_of_platforms" >= 15