Rails Ruby on Rails

ObjectItem HABTM ObjectGroup and ObjectGroup HABTM ObjectItem. I have the following query that is working correctly:

ObjectItem.find(:all, :include => :object_groups, :conditions => "object_items.description LIKE '%#{search}%' OR object_groups.description LIKE '%#{search}%'", :order => 'object_items.created_at DESC')

But doing query this way is now deprecated so i'm trying to change to this form

ObjectItem.order('object_items.created_at DESC').includes(:object_groups).where("object_items.description LIKE '%#{search}%' OR object_groups.description LIKE '%#{search}%'")

But i'm getting the following error:

Mysql2::Error: Column 'created_at' in order clause is ambiguous: SELECT DISTINCT object_items.id FROM object_items LEFT OUTER JOIN object_groups_object_items ON object_groups_object_items.object_item_id = object_items.id LEFT OUTER JOIN object_groups ON object_groups.id = object_groups_object_items.object_group_id WHERE (object_items.description LIKE '%%' OR object_groups.description LIKE '%%') ORDER BY object_items.created_at DESC, created_at DESC LIMIT 20 OFFSET 0