没有NOW函数？ 难道是sqlite的问题？

Request Method: GET
Request URL: http://127.0.0.1:8000/users/2/yetop/
Django Version: 1.1.1
Python Version: 2.6.4
Installed Applications:
['django.contrib.auth',
 'django.contrib.contenttypes',
 'django.contrib.sessions',
 'django.contrib.sites',
 'django.contrib.admin',
 'django.contrib.humanize',
 'forum',
 'django_authopenid']
Installed Middleware:
('django.middleware.gzip.GZipMiddleware',
 'django.contrib.sessions.middleware.SessionMiddleware',
 'django.middleware.common.CommonMiddleware',
 'django.contrib.auth.middleware.AuthenticationMiddleware',
 'django.middleware.transaction.TransactionMiddleware',
 'middleware.pagesize.QuestionsPageSizeMiddleware')


Traceback:
File "/usr/lib/python2.6/site-packages/django/core/handlers/base.py" in get_response
  92.                 response = callback(request, *callback_args, **callback_kwargs)
File "/home/bitbat/cnprog/forum/views.py" in user
  1019.     return func(request, id, user_view)
File "/home/bitbat/cnprog/forum/views.py" in user_stats
  1121.     votes_today = Vote.objects.get_votes_count_today_from_user(user)
File "/home/bitbat/cnprog/forum/managers.py" in get_votes_count_today_from_user
  218.             cursor.execute(self.COUNT_VOTES_PER_DAY_BY_USER, [user.id])
File "/usr/lib/python2.6/site-packages/django/db/backends/util.py" in execute
  19.             return self.cursor.execute(sql, params)
File "/usr/lib/python2.6/site-packages/django/db/backends/sqlite3/base.py" in execute
  193.         return Database.Cursor.execute(self, query, params)

Exception Type: OperationalError at /users/2/yetop/
Exception Value: no such function: NOW