Rails, includes with associations

Question

I have Country, Car, RentalType and CarType models.

Country Model
has_many :cars

Car Model
belongs_to :country
belongs_to :car_group

RentalType Model
has_many :car_rentals
has_many :cars, :through => :car_rentals
has_many :car_group_types
has_many :car_groups, :through => :car_group_types


CarGroup Model
has_many :cars
has_many :car_group_types
has_many :rental_types, :through => :car_group_types

So I would like to get the cars that belongs to the country, where it's rental type name is 'awake' and where it's car_group name is 'toyota'.

So far I have tried;

b = @country.cars.includes(:rental_types).where(:rental_types => { name: @rental_type.name } ).all

This works fine but when I try to add car group, it gives error;

b = @country.cars.includes(:rental_types).where(:rental_types => { name: @rental_type.name } ).where(:car_group => { name: @car_group.name } ).all

ERROR:

SQLite3::SQLException: no such column: car_group.name: SELECT DISTINCT COUNT(DISTINCT "cars"."id") FROM "cars" LEFT OUTER JOIN "car_rentals" ON "car_rentals"."car_id" = "cars"."id" LEFT OUTER JOIN "rental_types" ON "rental_types"."id" = "car_rentals"."rental_type_id" LEFT OUTER JOIN "car_groups" ON "car_groups"."id" = "cars"."car_group_id" WHERE "cars"."car_country_id" = ? AND "rental_types"."name" = ? AND "car_group"."name" = ?

Answer 1

• Add :car_group to your :includes :

  includes(:rental_types, :car_group)

• :car_group should be plural noun in your :where :

  where(:car_groups => { name: @car_group.name } )