django - 获取有多少模型包含整数大于 1 的子模型的计数

Question

class Company(models.Model):
    company = models.CharField(max_length=30, unique=True)
    create_date = models.DateTimeField(default=now, editable=False)

    def __str__(self):
        return self.company


class GroupAssessment(models.Model):
    company = models.ForeignKey(Company, on_delete=models.CASCADE, related_name='group_assessments')
    placibo_drug = models.CharField(max_length=10, blank=True)

    def __str__(self):
        return self.company.company


class UserAssessment(models.Model):
    group_assessment = models.ForeignKey(GroupAssessment, on_delete=models.CASCADE, related_name='user_assessments')
    risk = models.IntegerField()

假设有 2 个GroupAssessment，一个叫Apple另一个叫Microsoft：

>>> GroupAssessment.objects.all()
<QuerySet [<GroupAssessment: Apple>, <GroupAssessment: Microsoft>]>
# 2 groups

10UserAssessment属于GroupAssessment 微软。3个风险大于等于1。12个属于苹果，没有风险。

我如何计算有多少GroupAssessment具有UserAssessment风险greater than or equal to 1。

Answer 1

user_assessments您可以通过 id 和分组来实现此过滤：

    query = GroupAssessment.objects.filter(user_assessments__risk__gte=1).annotate(num_groups=Count('id'))
    print(query.num_groups)