title: How to perform OR condition in django queryset?
body: <p>I want to write a Django query equivalent to this SQL query:</p>
  
  <pre><code>SELECT * from user where income &gt;= 5000 or income is NULL.
  </code></pre>
  
  <p>How to construct the Django queryset filter?</p>
  
  <pre><code>User.objects.filter(income__gte=5000, income=0)
  </code></pre>
  
  <p>This doesn't work, because it <code>AND</code>s the filters. I want to <code>OR</code> the filters to get union of individual querysets.</p>