implementing Django ORM when handling complex queries with Subquery and OuterRef
Does anyone know how to After trying multiple solutions online, I still can't figure this out. Quick question that's been bugging me - I'm working with a question while trying to use Django's ORM to perform a complex query involving a subquery with `OuterRef`... My goal is to filter down a set of records based on a related model, but the results are not what I expect. Here's the code I'm using: ```python from django.db.models import OuterRef, Subquery, Count from myapp.models import Author, Book # I want to get authors with more than 3 books subquery = Book.objects.filter(author=OuterRef('pk')).values('author').annotate(book_count=Count('id')).values('book_count') authors = Author.objects.annotate(num_books=Subquery(subquery)).filter(num_books__gt=3) ``` When I run this, I get the following behavior: ``` Subquery returned more than one row: Django tried to execute a subquery that doesn't return a single value. ``` I have double-checked that an author can have multiple books, which is why I thought this should work with the subquery. I tried using `annotate()` directly on the `Book` queryset instead, but it didn't help. I also considered using `prefetch_related` for optimization, but I still need the same filtering logic. Has anyone encountered this scenario, or does anyone have a way to effectively rewrite this to achieve the desired filtering? I'm using Django version 3.2 and PostgreSQL as my database backend, which I believe should support these features. Any help would be appreciated! I'm working on a application that needs to handle this. Is there a better approach? For context: I'm using Python on Windows. This issue appeared after updating to Python 3.9.