Rails 4 - Как добавить «включает» модели в запрос с «joins»?

Question

У меня есть эти модели:

class Car < ActiveRecord::Base 
    has_many :shared_cars 
end 
class SharedCar < ActiveRecord::Base 
    belongs_to :car 
    belongs_to :owner 
    acts_as_mappable :through => :car 
end 
class Owner < ActiveRecord::Base 
    has_many :shared_cars 
end 
car Service < ActiveRecord::Base 
    has_many :car_services 
    has_many :cars, through: :car_services 
end 

А вот запрос я имею:

@cars = SharedCar.joins(:car) 
       .select('COUNT(cars.id) AS grouped_cars, 
          cars.registration, 
          cars.added_at') 
        .within(distance, origin: [lat,lng]) 

Но на этот запрос, я должен был бы добавить еще services. Я попытался

@cars = SharedCar.joins(:car).includes(:services) 
       .select('COUNT(cars.id) AS grouped_cars, 
          cars.registration, 
          cars.added_at') 
        .within(distance, origin: [lat,lng]) 

Ошибка:

Association named 'services' was not found; perhaps you misspelled it? 

Как правильно прикрепил модели услуг в запросе?

Answer 1

Возможно, это поможет!

class Car < ActiveRecord::Base 
    has_many :shared_cars 
    has_many :car_services ##added 
    has_many :services, through: :car_services ##added 
end 

, а затем в запросе

@cars = SharedCar.joins(car: :services) 
        .select('COUNT(cars.id) AS grouped_cars, 
           cars.registration, 
           cars.added_at') 
         .within(distance, origin: [lat,lng]) 

Answer 2

# car.rb 
class Car < ActiveRecord::Base 
    has_many :shared_cars 
    has_many :car_services 
end 

# And query with include 
@cars = SharedCar.joins(:car).includes(car: {car_services: :service}).select(
    'COUNT(cars.id) AS grouped_cars, 
    cars.registration, 
    cars.added_at' 
).within(distance, origin: [lat,lng]).references(:service)