Question

我有这些模特：

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

这是我的查询：

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

但是对于这个查询，我还需要添加services。我试过了

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

错误：

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

如何将模型服务正确附加到查询中？

Answer 1

可能有帮助！

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

然后在您的查询中

 @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)

Rails 4 - 如何使用“连接”向查询添加“包含”模型？

2 个答案: