Question

我有四个与餐馆有关的模型，我很难返回正确的结果。

模型为AdminEnteredRestaurant，Restaurant，Photo，Menu，定义如下：

class AdminEnteredRestaurant(models.Model):
    restaurant = models.OneToOneField(Restaurant)
    ...

class Restaurant(models.Model):
    name = models.CharField(max_length= 100)
    ...

class Photo(models.Model):
    restaurant = models.ForeignKey(Restaurant)
    ...

class Menu(models.Model):
    restaurant = models.OneToOneField(Restaurant)
    ...

我想要的查询是过滤所有AdminEnteredRestaurant并仅返回具有1个或更少AdminEnteredRestaurant个和0个菜单的Photo个compile ('com.ourcompany:sdk:2.1.16@aar') { transitive = true }。我该怎么做呢？

Answer 1

我会使用Count，annotate，lte和isnull来制作类似

的内容

from django.db.models import Count
results = AdminEnteredRestaurant.objects.annotate(num_photos=Count('restaurant__photo')) \
                                        .filter(num_photos__lte=1) \
                                        .filter(restaurant__menu__isnull =True)

根据Django中的对象计数过滤一对多关系

1 个答案: