simple way for QuerySet union and subtraction in django?

Question

Consider two QuerySet objects of the same class. Is there a simple way to unify them into a single QuerySet by calculating the union? Also, is there a simple way to subtract the

Answer 1

Subtract a QuerySet from another QuerySet using the same model.

This works - but is probably slowly

queryset_with_hello = Blog.objects.filter(name__icontains='hello')
queryset_without_hello = Blog.objects.exclude(pk__in=queryset_with_hello)

Read the performance considerations in django documentation:

https://docs.djangoproject.com/en/dev/ref/models/querysets/#in