title: Django - How to sort queryset by number of character in a field
body: <p>MyModel:</p>
  
  <pre><code>name = models.CharField(max_length=255)
  </code></pre>
  
  <p>I try to sort the queryset. I just think about this:</p>
  
  <pre><code>obj = MyModel.objects.all().sort_by(-len(name)) #???
  </code></pre>
  
  <p>Any idea?</p>