Question

我一直面临这个问题。我有 2 个具有如下关系的模型，我试图用过滤器总结每个作者的所有 PRICE：sale_type=sl01，但我一整天都被困住了。有人可以指出正确的方法来解决它，非常感谢，

from django.db.models import Q, Subquery, OuterRef

    SALE_CHOICES = (
        ("sl01", "sl01"),
        ("sl02", "sl02")
    )
    
    
    class Author(models.Model):
        created = models.DateTimeField(auto_now_add=True)
        name = models.CharField(max_length=50, default='', null=True)
        password = models.CharField(max_length=20, default='', null=True)
        phone = models.CharField(max_length=15, default='', null=True)
        address = models.CharField(max_length=100, default='', null=True)
    
    
    class Sale(models.Model):
        created = models.DateTimeField(auto_now_add=True)
        author = models.ForeignKey(Author, on_delete=models.CASCADE, null=True)
        price = models.DecimalField(max_digits=10, decimal_places=2, null=True)
        sale_type = models.CharField(choices=SALE_CHOICES, default='sl01', max_length=10)

    data = Author.objects.annotate(total_amount=Subquery(Sale.objects.filter(author=OuterRef('author'), sale_type='sl01').aggregate(total_amount=Sum('price'))['total_amount']))

Answer 1

您可以将 filter 关键字参数传递给聚合函数以过滤聚合。见Filtering on annotations [Django docs]

from django.db.models import Q, Sum


data = Author.objects.annotate(total_amount=Sum('sale__price', filter=Q(sale__sale_type='sl01')))

Django - 如何在注释中使用过滤器对相关模型字段求和？

1 个答案: