Django date field derived from timestamp field

Question

I have a created_date field:

class Comment(models.Model):
    created_date = models.DateTimeField(auto_now_add=True)

I want a field derived from created_date that ideally exists in the model. I know in SQL I can do:

SELECT created_date::date
FROM Comment

How would I define that in the Django model?

Edit: created_date is just an example so I can't use date.today() from datetime module. Also note ultimate goal is to make a slug with a few different fields include the desired 'date_only' field.

Answer 1

You can use the __date lookup ^[Django-doc] when filtering or in F-expression, or for older versions of Django you can use the TruncDate function ^[Django-doc].

So you can for example filter Comments for a specific date with:

from datetime import date

Comment.objects.filter(created_date__date=date(2022, 4, 9))

Using …_date however makes not much sense: it is a datetime object, so the name of your field hints that it is a DateField, it might be better to use created, or created_timestamp.