sample.rb

# current_account.time_blocks.recently_updated
# result -> lots of records

# current_account.appointments.recently_updated
# result -> NoMethodError Exception: undefined method `recently_updated' for #<Class:0x007fe6a7a13ef8>


class Appointment < ActiveRecord::Base
  belongs_to :time_block

  scope :recently_updated, includes(:time_block).where("time_blocks.updated_at > ?", 5.days.ago).order("time_blocks.updated_at desc").limit(50)
end

class TimeBlock < ActiveRecord::Base
  has_one :appointment
end