title: Two filters on two tables using prefetch_related
body: <p>Let's suppose this is my model:</p>
  
  <pre><code>class Pizza(models.Model):
      size = models.IntegerField()
      #other fields
  
  class Order(models.Model):
      date = models.DateField()
      pizza = models.ManyToManyField(Pizza, through='OrderPizza')
      #other fields
  
  
  class OrderPizza(models.Model):
      update = models.BooleanField()
      order = models.ForeignKey(Order, on_delete=models.CASCADE)
      pizza = models.ForeignKey(Pizza, on_delete=models.CASCADE)
  </code></pre>
  
  <p>I try to see within the last order the id of the pizza with size 32. <strong>How can I do that using only one queryset?</strong> </p>
  
  <pre><code>#I take the last order:
  last_order =  Orders.objects.filter().order_by('-order_number')[:1]
  
  #If we have at least one order
  if last_order:
      var_last_order_id = last_order[0].id
      #First filter
      queryset_orders = Orders.objects.filter(id=var_last_order_id).prefetch_related('pizza')
  
      for food in queryset_orders:
          #Second filter
          pizza32 = food.pizza.filter(size = 32)
          print pizza32.id
  </code></pre>