Django 字段错误：无法将关键字'total_sales'解析为字段

Question

这是我正在运行的查询，用于获取各方的总销售额。

Party.objects.annotate(total_sales=Sum('sales__salestransaction__total_cost'))

它显示了正确的结果。但是，当我尝试使用get_queryset在视图中应用时，它不起作用，并显示一个FieldError，它是：

无法将关键字"total_sales"解析到字段中。选项包括：party_address、party_id、party_name、party_phone、sales

我的视图

class PartyListView(ListView):    
paginate_by = 2
model = Party
template_name = 'mael/parties.html'
def querystring(self):
qs = self.request.GET.copy()
qs.pop(self.page_kwarg, None)        
return qs.urlencode()
def get_queryset(self):
qs = super().get_queryset()
if 'q' in self.request.GET:
search_txt = self.request.GET['q']           
qs = qs.filter(party_name__icontains=search_txt).annotate(total_sales=Sum('sales__salestransaction__total_cost'))

return qs.order_by('total_sales')
def get(self, request):
form = PartyForm()        
party_list = self.get_queryset()
qrstring = self.querystring()
paginator = Paginator(party_list, 5)
page_number = request.GET.get('page')
party_list = paginator.get_page(page_number)
return render(request, self.template_name, {'form': form, 'party_list': party_list, 'querystring': qrstring})

型号

class Party(models.Model):
party_id = models.BigAutoField(primary_key=True)
party_name = models.CharField(max_length=128)
party_phone = models.CharField(max_length=128)
party_address = models.CharField(max_length=128)        
def __str__(self):
return self.party_name

class Sales(models.Model):
invoice_no = models.BigAutoField(primary_key=True)
invoice_date = models.DateField(default=date.today)
party = models.ForeignKey(Party, on_delete=models.CASCADE)    
def __str__(self):
return str(self.invoice_no)
class SalesTransaction(models.Model):
sales = models.ForeignKey(Sales, on_delete=models.CASCADE)        
item_qty = models.PositiveIntegerField(default=0)
total_cost = models.PositiveIntegerField(default=0)
def __str__(self):
return self.item_name

get_queryset函数有什么问题？如何解决此错误？请帮忙

Answer 1

如果if 'q' in self.request.GET返回False，则不能使用.order_by('total_sales')，因此在这两种情况下都应该进行注释：

def get_queryset(self):
qs = super().get_queryset().annotate(
total_sales=Sum('sales__salestransaction__total_cost')
)
if 'q' in self.request.GET:
search_txt = self.request.GET['q']           
qs = qs.filter(party_name__icontains=search_txt)

return qs.order_by('total_sales')