title: Reduce queries to the same Django model when using Model.objects.all()
body: <p>I need to perform aggregate sum on multiple columns from the same model and currently there are 7 queries base on my current setup below</p>
  
  <pre><code>def traffic_list(request, template_name='traffic_list.html'):
      traffic = Traffic.objects.all()
      total_sessions = Traffic.objects.all().aggregate(Sum('sessions')).get('sessions__sum')
      total_new_users = Traffic.objects.all().aggregate(Sum('new_users')).get('new_users__sum')
      total_reminder = Traffic.objects.all().aggregate(Sum('reminder')).get('reminder__sum')
      total_campaigns = Traffic.objects.all().aggregate(Sum('campaigns')).get('campaigns__sum')
      total_new_sales = Traffic.objects.all().aggregate(Sum('new_sales')).get('new_sales__sum')
      total_sales_renewals = Traffic.objects.all().aggregate(Sum('sales_renewals')).get('sales_renewals__sum')
  </code></pre>
  
  <p>I know there has to be a DRY way of doing this.  Thank you for the help.</p>