Django REST：查询集错误类型错误 int() 必须是字符串

Question

我正在尝试获取所有雇主用户。 所以我所做的就是过滤可以在任何（其他）用户的“雇主”字段中找到 id 的用户。 但是，这给了我以下错误：

TypeError: int() argument must be a string, a bytes-like object or a number, not 'builtin_function_or_method'

查看：

# Get all employers
class Employers(viewsets.ModelViewSet):
    queryset = CustomUser.objects.all()
    serializer_class = CustomUserSerializer

    def list(self, request):
        #queryset = CustomUser.objects.all();
        queryset = self.queryset.filter(id__in=CustomUser.objects.filter(employer=id))    #this gives me an error
        serializer = CustomUserSerializer(queryset, many=True)
        return Response(serializer.data)
    

模型（标准的东西）：

# CustomUser model
class CustomUser(AbstractBaseUser):
    username = None
    email = models.EmailField(verbose_name='email address', max_length=255, unique=True)
    date_joined = models.DateTimeField(verbose_name='date joined', auto_now_add=True)
    last_login = models.DateTimeField(verbose_name='last login', auto_now=True)
    is_admin = models.BooleanField(default=False)
    is_active = models.BooleanField(default=True)
    is_staff = models.BooleanField(default=False)
    is_superuser = models.BooleanField(default=False)

    employer = models.ForeignKey("self", blank=True, null=True, on_delete=models.DO_NOTHING)

    USERNAME_FIELD = 'email'
    REQUIRED_FIELDS = []

    objects = MyUserManager()

    def __str__(self):
        return self.email

    def has_perm(self, perm, obj=None):
        return self.is_admin

    def has_module_perms(selfself, app_label):
        return True;
    

我不确定我做错了什么。有什么建议吗？

Answer 1

您可以使用F-expression [Django-doc] 过滤以引用另一列：

from django.db.models import F

class Employers(viewsets.ModelViewSet):
    queryset = CustomUser.objects.all()
    serializer_class = CustomUserSerializer

    def get_queryset(self, *args, **kwargs):
        return CustomUser.objects.filter(employer=F('pk'))

这使得查询看起来像;

SELECT customuser.*
FROM customuser
WHERE customuser.employer = customuser.id

或者您可以反向过滤关系以获得至少雇用一个人的CustomUsers：

class Employers(viewsets.ModelViewSet):
    queryset = CustomUser.objects.all()
    serializer_class = CustomUserSerializer

    def get_queryset(self, *args, **kwargs):
        return CustomUser.objects.filter(customuser__isnull=False).distinct()

这构造了一个如下所示的查询：

SELECT DISTINCT customuser.*
FROM customuser
JOIN customuser u2 ON u2.employer = customuser.id