temp_fields_1.rb

#models/user.rb
class User < ActiveRecord::Base
  has_one :address
  named_scope :with_city_info, 
              :joins=>:address, 
              :select="users.*, addresses.city as user_city"
end

#models/address.rb
class Address < ActiveRecord::Base
  belongs_to :user
end

#users controller
def locations
  @users = User.with_city_info
end