LEFT JOIN Django ORM

by

You can do this by following the backwards relation in the lookup.

>>> qs = Department.objects.filter(departmentvolunteer__isnull=True).values_list('name', flat=True)
>>> print(qs.query)
SELECT "app_department"."name" FROM "app_department" LEFT OUTER JOIN
"app_departmentvolunteer" ON ( "app_department"."id" = "app_departmentvolunteer"."department_id" )
WHERE "app_epartmentvolunteer"."id" IS NULL

Here are the docs on queries “Spanning multi-valued relationships”: https://docs.djangoproject.com/en/stable/topics/db/queries/#spanning-multi-valued-relationships

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