Rails: HABTM - find all records with no association

Question

I have 2 models (Workout, Equipment) in a has and belongs to many relationship. If I use Workout.find(:all, :joins => :equipment, :conditions => "equipment.id = 5") it works, but if I use Workout.find(:all, :joins => :equipment, :conditions => "equipment.id = null") it doesn't return the records with no association. Any ideas?

Jonis

Rails join is an inner join. Check out Jamsi's answer for left outer join which will give you the "unassociated workouts". – Honniball

possible duplicate of Rails habtm and finding record with no association – Cartography

Answer 1

Give this a whirl;

Workout.joins("left join equipments e on workouts.id = e.workouts_id").where("e.id is null")

Shaggy

rails 3 arel: Workout.joins(:equipments, Arel::Nodes::OuterJoin).where( Equipment.arel_table[:id].eq(nil) ) – Rafaellle