title: Laravel eloquent model query for `not null`
body: <p>I've been using Laravel for a project and using the Eloquent models to grab the model instances I need.</p>
  
  <p>However, it doesn't look like there's a way to query for <code>not null</code> values.</p>
  
  <p><a href="https://laravel.com/docs/5.4/eloquent#retrieving-models" rel="noreferrer">https://laravel.com/docs/5.4/eloquent#retrieving-models</a></p>
  
  <p>Is there a way to do something like this, where I want to get all <code>Flight</code> models where the <code>ticket_id</code> is <code>not null</code>?</p>
  
  <pre><code>$flight = App\Flight::where('ticket_id', '!=', null);
  </code></pre>