Django filter using DateTimeField that can be null

July 20, 2022

I want to filter a table objects using a DateTimeField => last_user_action_time, this field can be null so I need the cases where its null to be included in the result.

Here is what I tried:

notification_objects = SinglePushNotification.objects.filter(
            last_user_action_time__lte=day_start,
            last_user_action_time__isnull=True,
        ).select_related("customer")

This return an empty querySet knowing there is objects where null=True

>Solution :

Sounds like you need to use an or query, in your attempt you are checking that both conditions are true: field is null and date is less than start (impossible case).

Try an or like so:

from django.db.models import Q

notification_objects = SinglePushNotification.objects.filter(
            Q(last_user_action_time__lte=day_start) |
            Q(last_user_action_time__isnull=True)
        ).select_related("customer")