GAE DateTimeProperty index

gistfile1.py

from datetime import datetime, timedelta
from google.appengine.ext import db

class Foo(db.Model):
    value = db.DateTimeProperty()

db.delete(Foo.all())

Foo(value=None).put()
Foo(value=datetime.now()).put()
Foo(value=datetime.now()).put()

print Foo.all().count()  # 3
print Foo.all().filter('value >', datetime.now()-timedelta(minutes=1)).count()  # 2
print Foo.all().filter('value <', datetime.now()).count()  # 3
print Foo.all().filter('value =', None).count()