Question

I have got model Team and I’ve got (i.e.) team = Team.first :offset => 20. Now I need to get number of position of my team in db table.

I can do it in ruby:

Team.all.index team #=> 20

But I am sure that I can write it on SQL and it will be less expensive for me with big tables.

Answer 1

Assuming the order is made by ID desc:

class Team < ActiveRecord::Base
  def position
    self.class.count(:conditions => ['id <= ?', self.id]) 
  end
end