What is the method of filtering a QuerySet depending on the existence of its objects in a different model?

edit

The method for filtering a QuerySet depending on the existence of its objects in a different model in Django is to use the __in lookup.

For example, if you have a model called Book and another model called Author, and you want to filter all the books written by a specific author, you can do the following:

author = Author.objects.get(name='J.K. Rowling')
books = Book.objects.filter(author__in=[author])

In this example, we first get the author object for J.K. Rowling from the Author model, and then we use the __in lookup to filter all the books that have that author. This will return a QuerySet of Book objects that match the filter criteria.