问题:

I want to write a Django query equivalent to this SQL query:

SELECT * from user where income >= 5000 or income is NULL.

How to construct the Django queryset filter?

User.objects.filter(income__gte=5000, income=0)

This doesn't work, because it ANDs the filters. I want to OR the filters to get union of individual querysets.

回答1:

from django.db.models import Q
User.objects.filter(Q(income__gte=5000) | Q(income__isnull=True))

via Documentation

回答2:

Because QuerySets implement the Python __or__ operator (|), or union, it just works. As you'd expect, the | binary operator returns a QuerySet so order_by(), .distinct(), and other queryset filters can be tacked on to the end.

combined_queryset = User.objects.filter(income__gte=5000) | User.objects.filter(income__isnull=True)
ordered_queryset = combined_queryset.order_by('-income')