active admin sort a count of a has_many column

问题

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?

回答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

来源：https://stackoverflow.com/questions/21744609/active-admin-sort-a-count-of-a-has-many-column