You could do this:
If you need to exclude null values and empty strings, the preferred way to do so is to chain together the conditions like so:
Chaining these methods together basically checks each condition independently: in the above example, we exclude rows where
alias is either null or an empty string, so you get all
Name objects that have a not-null, not-empty
alias field. The generated SQL would look something like:
SELECT * FROM Name WHERE alias IS NOT NULL AND alias != ""
You can also pass multiple arguments to a single call to
exclude, which would ensure that only objects that meet every condition get excluded:
Here, rows in which
other_field are true get excluded, so we get all rows where both fields are not true. The generated SQL code would look a little like this:
SELECT * FROM Name WHERE NOT (some_field = TRUE AND other_field = TRUE)
Alternatively, if your logic is more complex than that, you could use Django’s Q objects:
from django.db.models import Q Name.objects.exclude(Q(alias__isnull=True) | Q(alias__exact=""))
For more info see this page and this page in the Django docs.
As an aside: My SQL examples are just an analogy–the actual generated SQL code will probably look different. You’ll get a deeper understanding of how Django queries work by actually looking at the SQL they generate.