title: Nested select using laravel query builder
body: <p>I'm trying to find a way to convert this raw SQL into a laravel query builder:</p>
  
  <pre><code>SELECT value1,value2 
  FROM foo
  WHERE id NOT IN(
     SELECT id 
     FROM foo 
     HERE foo.key = 'client_location_id');
  </code></pre>
  
  <p>I've looked through the laravel docks but there isn't any clear outlined way of converting nexted selects into their query builder version.</p>