find all that are nil in the association

Question

So I have a Post and a User.
Post has_many users and a user belongs_to a post.
I need a find that will find all the Posts that dont have any users like the following:

Answer 1

Post.first.users.empty? should be sufficient if users returns an array.

If you want to check for each post you could do

Post.each do |p|
  if p.users.empty?
    do whatever
  end
end