Tales on Rails: The Three Little Devs

brick.rb

class Order < ActiveRecord::Base
  #...

  def self.with_profit_of_at_least(amount)
    where { profit >= amount }
  end
end

class Customer < ActiveRecord::Base
  #...
  
  def self.big_spenders
    joins(:orders).uniq.merge(
      Order.high_margin.with_profit_of_at_least(25000))
  end
end