How to do many-to-many Django query to find book with 2 given authors?

Question

I have a query that requires to filter exactly 2 authors with the ID

Theoretically,

Book.objects.filter(author__id=1, author__id=2). 

Answer 1

New questions are pointing to this one as a duplicate, so here is an updated answer (for one specific backend).

If the backend is Postgres, the SQL you want is (assuming the M2M table is called bookauthor):

SELECT *
FROM book
WHERE
    (SELECT ARRAY_AGG(bookauthor.author_id)
     FROM bookauthor
     WHERE bookauthor.book_id = book.id) = Array[1, 2];

You can get Django to generate nearly this SQL.

First, pip install django-sql-utils. Then create this Array class:

from django.db.models import Func

class Array(Func):
    function = 'ARRAY'
    template = '%(function)s[%(expressions)s]'

And now you can write your ORM queryset:

from sql_util.utils import SubqueryAggregate
from django.contrib.postgres.aggregates import ArrayAgg

books = Book.objects.annotate(
            author_ids=SubqueryAggregate('author__id', Aggregate=ArrayAgg)
        ).filter(author_ids=Array(1, 2))