How to combine multiple QuerySets in Django?

Concatenating the querysets into a list is the simplest approach. If the database will be hit for all querysets anyway (e.g. because the result needs to be sorted), this won’t add further cost.

from itertools import chain
result_list = list(chain(page_list, article_list, post_list))

Using itertools.chain is faster than looping each list and appending elements one by one, since itertools is implemented in C. It also consumes less memory than converting each queryset into a list before concatenating.

Now it’s possible to sort the resulting list e.g. by date (as requested in hasen j’s comment to another answer). The sorted() function conveniently accepts a generator and returns a list:

from operator import attrgetter
result_list = sorted(
    chain(page_list, article_list, post_list),
    key=attrgetter('date_created')
)

You can reverse the sort order:

result_list = sorted(
    chain(page_list, article_list, post_list),
    key=attrgetter('date_created'),
    reverse=True,
)

attrgetter is equivalet to the following lambda (this was the way it had to be done before Python 2.4):

result_list = sorted(
    chain(page_list, article_list, post_list),
    key=lambda instance: instance.date_created,
)