Django 对除查询项之外的模型实例进行注释使用

发布于 2024-11-17 05:29:02 字数 555 浏览 3 评论 0原文

我有一个查询，

em =Employer.objects.filter(id=1).annotate(overall_value = Sum('companyreview__overallRating'))

em[0].overall_value

如您所见，我想要对 employer 具有 id = 1 的所有 companyreview 对象的 overallRating 字段进行求和。

上面的查询满足了我的要求，但我确信有一种方法可以从 Employer 实例获取总和。

我怎样才能像这样实现这个查询

em =Employer.objects.get(id=1)
rate = em.companyreview_set.all().annotate(overall_value = Sum('overallRating'))
rate.overall_value

？

谢谢

原文

I have a query such that

em =Employer.objects.filter(id=1).annotate(overall_value = Sum('companyreview__overallRating'))

em[0].overall_value

As you see I want to sum of overallRating field of all companyreview objects whose employer has id = 1.

The query above does what I want but I am sure that there is a way to get the sum from an Employer instance.

How can I implement this query like

em =Employer.objects.get(id=1)
rate = em.companyreview_set.all().annotate(overall_value = Sum('overallRating'))
rate.overall_value

Thanks

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明明#如月 2024-11-24 05:29:02

使用聚合：

e.companyreview_set.aggregate(overall_value = Sum('overall_rating'))

对于：

class Employer(models.Model): 
     name = models.CharField(max_length=100)

class CompanyReview(models.Model): 
     employer = models.ForeignKey(Employer)
     overall_rating = models.IntegerField()

Use aggregate:

e.companyreview_set.aggregate(overall_value = Sum('overall_rating'))

For:

class Employer(models.Model): 
     name = models.CharField(max_length=100)

class CompanyReview(models.Model): 
     employer = models.ForeignKey(Employer)
     overall_rating = models.IntegerField()

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