Django 查询 __isnull=True 或 = None

Question

这是一个简单的问题。我想知道这样写是否相同:

queryset = Model.objects.filter(field=None)

比:

queryset = Model.objects.filter(field__isnull=True)

我正在使用 Django 1.8

Answer 1

他们是平等的:

>>> str(Person.objects.filter(age__isnull=True).query) == str(Person.objects.filter(age=None).query)
True
>>> print(Person.objects.filter(age=None).query)
SELECT "person_person"."id", "person_person"."name", "person_person"."yes", "person_person"."age" FROM "person_person" WHERE "person_person"."age" IS NULL
>>> print(Person.objects.filter(age__isnull=True).query)
SELECT "person_person"."id", "person_person"."name", "person_person"."yes", "person_person"."age" FROM "person_person" WHERE "person_person"."age" IS NULL

排除:Postgres JSON 字段(见@cameron-lee 的回答)