active admin sort a count of a has_many column

Question

Using the Active Admin framework, I can add a 'users' column that totals the count for a particular 'club' by doing this:

ActiveAdmin.register Club do
  index do
    column 'Users' do |club|
      club.users.count
    end
  end
end

Can I make this sortable somehow?

Answer 1

You could add a counter cache column on teh User model's belongs_to :club, and then make your index like so:

ActiveAdmin.register Club do
  index do
    column 'Users', sortable: :users_count do |club|
      club.users.count
    end
  end
end