title: How to filter queryset not equal to in Django?
body: <p>I have models called Stores and SaleItems which look some what like this.</p>
  
  <pre><code>class Stores(models.Model):
      name = models.CharField(unique=True, max_length=20)
  
  
  class SaleItems(models.Model):
      sale_by = models.ForeignKey(Stores)
      start_date = models.DateTimeField()
      end_date = models.DateTimeField()
  </code></pre>
  
  <p>So I need to retrieve sale items based on the following conditions.</p>
  
  <ol>
  <li>If its not my store, then leave out items having start_date greater than today and end_date lesser than today.</li>
  <li>If its my store, then get items irrespective of start_date and end_date.</li>
  </ol>
  
  <p>So in my views.py, this is how far I have come up.</p>
  
  <pre><code>class SaleItemsView(viewsets.ModelViewSet):
      querys = SaleItems.objects.all()
  
  
  def get_queryset(self):
      #get my store id
      store_id = self.request.query_params.get('store_id')
      querys = SaleItems.objects\
              .exclude(store__ne=store_id, end_date__lt=timezone.now())\
              .exclude(store__ne=store_id, start_date__gt=timezone.now())
      return querys
  </code></pre>
  
  <p>But it seems django doesn't have not equal operator any more. Is there any other way I can achieve this?</p>