[英]One to many queries in Django
這是我的City對象:
class City(Base):
country = models.ForeignKey(Country, on_delete=models.CASCADE)
name = models.CharField(max_length=255)
latitude = models.FloatField()
longitude = models.FloatField()
這是我的用戶:
class User(AbstractBaseUser, PermissionsMixin, Base):
username = models.CharField(db_index=True, null=False, unique=True, max_length=255)
mobile = models.CharField(db_index=True, max_length=100, null=True, unique=True)
city = models.ForeignKey(City, on_delete=models.CASCADE, null=True)
如何查詢擁有1個以上用戶的城市?
使用注釋:
from django.db.models import Count
City.objects.annotate(user_count=Count("user")).filter(user_count__gt=1)
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