如何通过按字段总和排序的外键分组进行查询

Question

例如我有一个模型：

class Reward(models.Model):
   user = models.ForeignKey(UserProfile)
   amount = models.IntegerField()

我想得到这样的统计数据：

[{ 
   "user": user1,
   "total_amount": 100500, // Sum of amount field of all rewards for this user
   "total_rewards": 13 // Count of rewards for this user
},
{
   "user": user2,
   ...
}
]

此列表应按 total_amount 字段排序。我该如何查询？

Answer 1

你可以用 annotate

from django.db.models import Count, Sum
UserProfile.objects.annotate(
    total_amount=Sum('reward__amount'),
    total_rewards=Count('reward')
).values('id', 'total_amount', 'total_rewards').order_by('total_amount')

如何通过按字段总和排序的外键分组进行查询

How to make query with grouping by foreign keys with ordering by sum of field

django

django-queryset