How do I map fields to each other?

To map a more specific set of fields (such as city names) to a more general set of fields (such as region names), use the case statement.

map cities to regions

Use the case function to map fields.

make_col region:case(city="Alhambra", "California",
    city="Anaheim", "California",
    city="Burbank", "California",
    city="Carlsbad", "California",
    city="Cerritos", "California",
    city="Culver City", "California",
    city="Eureka", "California",
    city="Fresno", "California",
    city="Inglewood", "California",
    city="Merced", "California",
    city="Mount Shasta", "California",
    city="Oakland", "California",
    city="Pacific Palisades", "California",
    city="Redding", "California",
    city="Riverside", "California",
    city="Sacramento", "California",
    city="San Clemente", "California",
    city="San Diego", "California",
    city="San Jose", "California",
    city="Santa Monica", "California",
    city="Sherman Oaks", "California",
    city="Vacaville", "California",
    city="Vallejo", "California",
    city="West Covina", "California",
    true, city)