How to return an empty ActiveRecord relation?

If I have a scope with a lambda and it takes an argument, depending on the value of the argument, I might know that there will not be any matches, but I still want to return a relation, not an empty array: scope :for_users, lambda { |users| users.any? ? where("user_id IN (?)", users.map(&:id).join(',')) : [] } What I really want is a "none" method, the opposite of "all", that returns a relation th

[plasma0713]

“>> Model.none => #<ActiveRecord::Relation []>”

[nyangry]

activerecordで空配列風にactiverecordを返す方法。Rails4ならデフォでnoneでできる。