过滤查询集，应用多个过滤器

Question

我的模型是：

models.User:
       id = pk
       username = text

    models.Offer
       id = pk           
       description = text
       publicationDate = Date
       user = Fk(User)

    my serializer is:

    class UserOfferSerializer(ModelSerializer):
        offers = OfferSerializerAll(many=True, read_only=True)
        class Meta:
            model = User
            fields = ('id', 'username', 'offers')

我正在尝试在查询集上应用多个过滤器：

users = users.filter(offers__publicationDate__range=[startdate, enddate]). prefetch_related(Prefetch('offers', queryset=Offer.objects.filter(
publicationDate__range=[startdate, enddate]))).distinct()

然后

users = users.filter(offers__description__icontains=sometext).prefetch_related(Prefetch('offers', queryset=Offer.objects.filter(description__icontains=sometext))).distinct()

第一个工作正常，另一个抛出以下异常：

ValueError: 'offers' lookup was already seen with a different queryset. You may need to adjust the ordering of your lookups.

更新：

我当前的代码是：

    if (offerBeginDate != None and offerEndDate != None):
        b = offerBeginDate.split('-')
        e = offerEndDate.split('-')

        startdate = datetime.date(int(b[0]), int(b[1]), int(b[2]))
        enddate = datetime.date(int(e[0]), int(e[1]), int(e[2]))

        users = users.filter(offers__publicationDate__range=[startdate, enddate])
        offers = offers.filter(publicationDate__range=[startdate, enddate])

    if (descriptionText != None):

        users = users.filter(offers__functionDescription__icontains=descriptionText.strip())
        offers = offers.filter(functionDescription__icontains=descriptionText.strip())


    users = users.prefetch_related('offers', Prefetch(queryset=offers))

有什么帮助吗？谢谢大家:)))

Answer 1

您可以使用Prefetch 对象的to_attr 参数来预取额外的查询集：

users = users.filter(offers__description__icontains=sometext).prefetch_related(
        Prefetch('offers', queryset=Offer.objects.filter(
publicationDate__range=[startdate, enddate]), to_attr='date_offers'), 
        Prefetch('offers', queryset=Offer.objects.filter(description__icontains=sometext), to_attr='description_offers')).distinct()

UPD

如果您需要为预取的查询集动态添加过滤器，您可以像这样单独定义它：

if some_case:
    users = users.filter(offers__description__icontains=sometext)
    offers=Offer.objects.filter(description__icontains=sometext)
if some_case_2:
    users = users.filter(**conditions)
    offers = offers.filter(**conditions)

users = users.prefetch_related(Prefetch('offers', queryset=offers))

现在 users 查询集中的每个用户都有两个属性：user.date_offers 和 user.description_offers。