根据另一个字段 django 获取总和

Question

我有这些型号：

status_choices = ['not received', 'received']

class Investment(Model):
    # Offering
    offering = models.ForeignKey(Offering, blank=False, null=False, on_delete=models.CASCADE)
    invested = models.DecimalField(max_digits=9, default=0, decimal_places=2, blank=True, null=True)
    status = models.CharField(max_length=200, choices=status_choices, blank=True, null=True, default='not received')
    
class Offering(Model):
    
    ...

我想制作一个属性来显示 Offering 模型中所有投资的总和。

我是这样做的：

    @property
    def amount_invested(self):
        return Investment.objects.filter(offering_id=self.id).aggregate(Sum('invested'))['invested__sum'] or 0

但是，我还想显示 amount_invested 当且仅当 Investment 模型中的 status 是 'received'。

我可以知道我应该怎么做吗？

Answer 1

您可以过滤 investment_set，从而仅保留 status='received' 的 Investment：

@property
def amount_invested(self):
    return self.investment_set.filter(
        <strong>status='received'</strong>
    ).aggregate(Sum('invested'))['invested__sum'] or 0

根据另一个字段 django 获取总和

get sum based on another field django

django

django-models