How do you check if associated table is empty from find?

rubyonrails-talk
1

So I have two tables:

- teams - players

I'm trying to find all teams that have no players. I thought this could work:

Team.find(:all, :joins => :players, :conditions => ["players.size = ?", 0] )

Of course that's not working for me because I'm mixing the SQL with Rails. Do you know the proper way to find all teams that have no players?

2

You could add a :counter_cache to your model if you want a simple solution: