title: How can I do a right outer join in a Rails controller?
body: <p>In a Rails controller, I'm setting a variable like this:</p>
  
  <pre><code>@users = User.find(:all, :joins =&gt; family)
  </code></pre>
  
  <p>This gives me all the users that have families. What I want is exactly the opposite: all the users that <strong>don't</strong> have families.</p>
  
  <p>I tried adding:</p>
  
  <pre><code>:conditions=&gt; {:family =&gt; nil}
  </code></pre>
  
  <p>... but got an error.</p>
  
  <p>What's the proper way to do a right outer join?</p>