Django-对多个字段和进行分组

Django 2.1、python3.6

我有两个模型

house = (
    ('Clubs','Clubs'),
    ('Diamonds','Diamonds'),
    ('Hearts','Hearts'),
    ('Spades','Spades'),
    )

class Card(models.Model):
    id           = models.CharField(max_length=36, blank=False, primary_key=True)
    card         = models.CharField(max_length=15, blank=False)
    number       = models.IntegerField(default=1)
    house        = models.CharField(choices=house)

class Deck(models.Model):
    id       = models.CharField(max_length=50, primary_key=True)
    name     = models.Charfield(...)
    card        = models.ManyToManyField(Card, through='DeckCard')

class DeckCard(models.Model):
    deck = models.ForeeignKey(Deck, on_delete=models.cascade)
    card  = models.ForeignKey(Card, on_delete=models.CASCADE)

    @property
    def number_sum(self):
        self._number_sum= self.card.aggregate(total=models.Sum('number'))['total']
        return number_sum

属性字段 number_sum 成功返回正确的计数。不过,我现在想按 house

卡看起来应该在哪里

id...name........number...house
1....ace_diamonds..1......diamonds
2....two_diamonds..2......diamonds
3....three_diamonds..3....diamonds
4....four_diamonds...4....diamonds
...
52...king_Spades...13....spades

甲板看起来像

id...name
1...johnsdeck
2...bettysdeck

假设DeckCard如下所示

deck..card
1...ace_diamonds
1...two_diamonds
1...ace_diamonds (yes there can be duplicates)
1...three_hearts
2...ace_hearts

Deck 是每个人的一套卡片。 DeckCard 是牌堆里的实体牌。和 Card 包含卡上的属性。

所以在这个例子中,我希望有一个总计数和每个房子的计数 甲板1 总计:7(1+2+1+3) 心脏:3 黑桃:0

甲板2 总计:1 红心:1

self._number_sum= self.card.aggregate(total=models.Sum('number')) group by 这样除了总数之外,我还可以计算每间房子的总数。有人知道怎么做吗。

{  
  card: ...
  numbers: {
            Total:1
            Diamonds:4
            Clubs:0
            Hearts:3
            Spades:0
            }
}

但这不是为了这个问题。我敢肯定最好放在 @property