仅在Django中的注释上进行过滤 [英] Filtering only on Annotations in Django

问题描述

以下列示例：
http://docs.djangoproject.com/en/dev/topics/db/aggregation/#filter-and-exclude

  Publisher.objects.filter（book__rating__gt = 3.0）.annotate（num_books = Count（'book'））
  

是否有过滤器仅适用于注释，所以它会返回所有发布者，有些具有num_books = 0？

解决方案

您可以在过滤器中使用注释变量。

  publishers = Publisher.objects.annotate num_books = Count（'book'））filter（num_books__gte = 2）
  

Taking the example from: http://docs.djangoproject.com/en/dev/topics/db/aggregation/#filter-and-exclude

Publisher.objects.filter(book__rating__gt=3.0).annotate(num_books=Count('book'))

Is there anyway to have the filter only apply to the annotation, so it would return all publishers, with some having a num_books=0?

解决方案

You can use the annotation variable in the filter.

publishers=Publisher.objects.annotate(num_books=Count('book')).filter(num_books__gte=2)

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