gistfile1.rb

  named_scope :bill_on, lambda { |*args|
    date_to_bill = args[0]||Time.now.to_date
    if date_to_bill.day < 27
      { :conditions => "DAY(billing_date) = #{date_to_bill.day}" }
    else
      offset = date_to_bill.end_of_month.day - date_to_bill.day
      { :conditions => "( DAY(LAST_DAY(CURRENT_DATE))-DAY(billing_date) ) = #{offset}" }
    end
    }
  end