Question

I have models:

class Model < ActiveRecord::Base
  has_many :model2
end
class Model2 < ActiveRecord::Base
  belongs_to :model
  belongs_to :model3
end
class Model3 < ActiveRecord::Base
  has_many :model2
end

Model3 has field in db label. How could I find Model by Model3 label?

Answer 1

With “joins” you can filter results according to linked models

Model.joins(:model2s => :model3).where('model3.label' => 'label')

This will create only on db call, so it is very efficient. But joins can create duplicates when there is more than one way from model to model3. If this is possible then you need to add

Model.select("DISTINCT model.*").joins(:model2s => :model3).where('model3.label' => 'label')