什麼是寫下面的代碼的Rails的3.1:的Rails 3.1 named_scope
named_scope :min_2_items_last_90_days, {
:include => { :orders => :order_items },
:conditions => ['orders.created_at >= ?', 90.days.ago],
:group => 'people.id',
:having => 'COUNT(order_items.id) >= 2'
}