How do you scope ActiveRecord associations in Rails 3?

Question

I have a Rails 3 project. With Rails 3 came Arel and the ability to reuse one scope to build another. I am wondering if there is a way to use scopes when defining a relationsh

Answer 1

I use something like:

class Invoice < ActiveRecord::Base
  scope :aged_0,  lambda{ where("created_at IS NULL OR created_at < ?", Date.today + 30.days).joins(:owner) }
end