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Using aggregates within a Subquery expression in django

Anies answered on October 7, 2022 Popularity 6/10 Helpfulness 2/10

answer Using aggregates within a Subquery expression in django

Using aggregates within a Subquery expression in django

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#Aggregates may be used within a Subquery, but they require a specific combination of filter(), values(), and annotate() to get the subquery grouping correct.
#Assuming both models have a length field, to find posts where the post length is greater than the total length of all combined comments:
>>> from django.db.models import OuterRef, Subquery, Sum
>>> comments = Comment.objects.filter(post=OuterRef('pk')).order_by().values('post')
>>> total_comments = comments.annotate(total=Sum('length')).values('total')
>>> Post.objects.filter(length__gt=Subquery(total_comments))

Popularity 6/10 Helpfulness 2/10 Language python

Source: docs.djangoproject.com

Tags: aggregates django expression python subquery using

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