Rails: Find rows without connection in HABTM relation

Question

I have two models, Users and Leads connected with HABTM relation:

class Lead < ActiveRecord::Base
  has_and_belongs_to_many :use         


        

Answer 1

You can use a left join. Assuming your join table is named leads_users:

Lead.joins('LEFT JOIN leads_users ON leads_users.lead_id = leads.id').
     where(leads_users: { user_id: nil })