Django多连接查询

Question

我是新来的django，需要做一个查询。我可以在sql中完成，但我似乎无法在django中找到它。这里是在SQL中。有人能告诉我如何在Django中做到这一点。

select token from api_userprofile 
join api_userdevice on api_userdevice.user_id=api_userprofile.user_id 
join api_device on api_device.id=api_userdevice.device_id 
where api_device.serial=3 

我的模式是这样的：

class UserDevice(models.Model): 
    user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.PROTECT, null=False) 
    device = models.ForeignKey(Device, on_delete=models.PROTECT, null=False) 
    activation_date = models.DateTimeField(default=timezone.now, null=False) 
    friendly_name = models.CharField(max_length=20, null=True, blank=True) 
    is_owner = models.BooleanField(null=False, default=False) 
    is_admin = models.BooleanField(null=False, default=True) 

class Device(models.Model): 
    serial = models.CharField(max_length=16, null=False, unique=True) 
    publickey = models.CharField(max_length=44, null=False) 

class UserProfile(models.Model): 
    user = models.ForeignKey(settings.AUTH_USER_MODEL,on_delete=models.PROTECT, null=False) 
    token = models.TextField(null=False, blank=True) 

Answer 1

如果我理解正确的，你可以尝试：

users_pks = UserDevice.objects.filter(device__serial=3).values_list('user__pk') 
qs = UserProfile.objects.filter(user__pk__in=users_pks).values('token') 

进行检查SQL查询，您可以打印：

print (qs.query)