ActiveRecord find all parents that have associated children

Question

I don\'t know why I can\'t figure this out, I think it should be fairly simple. I have two models (see below). I\'m trying to come up with a named scope for SupplierCatego

Answer 1

class SupplierCategory < AR
  has_many :supliers

  def self.with_supliers
    self.all.reject{ |c| c.supliers.empty? }
  end
end

SupplierCategory.with_supliers
#=> Array of SuplierCategories with supliers

Another way more flexible using named_scope

class SupplierCategory < AR
  has_many :supliers
  named_scope :with_supliers, :joins => :supliers, :select => 'distinct(suplier_categories.id), suplier_categories.*', :having => "count(supliers.id) > 0"
end

SupplierCategory.with_supliers(:all, :limit => 4)
#=> first 4 SupplierCategories with suppliers