How to join one HABTM model by values of another?

Asked Jan 26 '16 at 18:07

Active Jan 26 '16 at 20:16

Viewed 45 times

I have three models:

class Campaign < ActiveRecord::Base
  has_and_belongs_to_many :models
  has_and_belongs_to_many :makes

class Make < AR::Base
  has_and_belongs_to_many :campaigns
  has_many :models

class Model
  has_and_belongs_to_many :campaigns
  belongs_to :make

I have a @campaign variable and a special @campaign.models value.

How can I find all makes that are related to @campaign.models?

The simplest solution is Make.where(id: @campaign.models.pluck(:make_id), but it's not efficient.

edited Jan 26 '16 at 20:16

the Tin Man

158,662
42
215
303

asked Jan 26 '16 at 18:07

Alex Antonov

14,134
7
65
142

1

Why won't that be efficient? – Mark Swardstrom Jan 26 '16 at 18:14
Makes.where(:id => @campaign.models.pluck(:make_id) ) or you can use join query. – Shefalee Chaudhary Jan 26 '16 at 18:33
1

try add `has_many :models_makes, through: :models, class_name: Make` – Oleh Sobchuk Jan 26 '16 at 18:34

How to join one HABTM model by values of another?

0 Answers0