Django F expression on datetime objects

Question

My model is:

class Test():
   date1 = models.DateTimeField()
   date2 = models.DateTimeField()

I can find out objects who's date2 is greater than date1, using the following query:

Test.obejcts.filter(date2__gt=F('date1'))

I would like to find all the objects who's date2 is greater than date1 by one year.
How can I find out objects based on difference between date1 and date2?

Answer 1

General Solution:

You can annotate the date difference and then check this against the timedelta(days=365) (pretty close to what @Anonymous suggests in his comment):

Test.objects.annotate(
    duration=F('date2') - F('date1')
).filter(duration__gt=timedelta(days=365))

---

PostgreSQL Specific Solution:

If you are using PostgreSQL, there is another option derived from this answer:

from django.db.models import F, Func

Test.objects.annotate(
    duration = Func(F('date2'), F('date1'), function='age')
).filter(duration__gt=timedelta(days=365))