CREATE TABLE county_public_safety (Police_force VARCHAR, LOCATION VARCHAR)

Show the police force shared by counties with location on the east and west.
SELECT Police_force FROM county_public_safety WHERE LOCATION = "East" INTERSECT SELECT Police_force FROM county_public_safety WHERE LOCATION = "West"
SELECT "Police_force" FROM "county_public_safety" WHERE "East" = "LOCATION" INTERSECT SELECT "Police_force" FROM "county_public_safety" WHERE "LOCATION" = "West"