CREATE TABLE school_bus (school_id DECIMAL, driver_id DECIMAL, years_working DECIMAL, if_full_time others)
CREATE TABLE school (school_id DECIMAL, grade TEXT, school TEXT, location TEXT, type TEXT)
CREATE TABLE driver (driver_id DECIMAL, name TEXT, party TEXT, home_city TEXT, age DECIMAL)

Show all home cities except for those having a driver older than 40.
SELECT home_city FROM driver EXCEPT SELECT home_city FROM driver WHERE age > 40
SELECT "home_city" FROM "driver" EXCEPT SELECT "home_city" FROM "driver" WHERE "age" > 40