How to add annotate data in django-rest-framework queryset responses

0 votes

I am generating aggregates for each item in a QuerySet:

def get_queryset(self):
    from django.db.models import Count
    queryset = Book.objects.annotate(Count('authors'))
    return queryset

But I am not getting the count in the JSON response.

thank you in advance

Jun 25, 2020 in Python by kartik
• 37,530 points
2,770 views

1 answer to this question.

0 votes

Hello @kartik,

The queryset returned from get_queryset provides the list of things that will go through the serializer, which controls how the objects will be represented. Try adding an additional field in your Book serializer, like:

author_count = serializers.IntegerField(
    source='author_set.count', 
    read_only=True
)

Hope this helps!!

answered Jun 25, 2020 by Niroj
• 82,820 points

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