Question

I’m trying to join two tables: Rooms and Room_Types (which have a relationship already). The thing is, I’m trying to do something like:

room = Room.all :conditions => ['rooms.id = ?', @room_id],
                :joins      => :room_type

room.to_json

..and this JSON is being sent to my view.

However, the JSON is only showing the fields of the Room table and is not including the Room_Type fields, and I need both tables’ fields in this JSON. How can I accomplish this?

Answer 1

:joins only performs a JOIN. As in SQL, this does not add the JOINed table’s columns to the results. If you want to do that you should use :include instead:

rooms = Room.all :conditions => [ 'rooms.id = ?', @room_id ],
                 :include    => :room_type
rooms.to_json

Or, in Rails 3 parlance:

rooms = Room.where(:id => @room_id).include(:room_type).all
rooms.to_json