Python-сообщество

from django.db import models
class DateTest (models.Model):
    name = models.CharField (max_length=10, unique = True)
    bool_1 = models.BooleanField ()
    date_reg = models.DateTimeField (null=True, blank=True, u'Дата регистрации')
    bool_2 = models.BooleanField (default = 0)
    error_msg = models.CharField(blank=True, max_length=300, verbose_name=u'Ошибка')
    comment = models.CharField(blank=True, max_length=100, verbose_name=u'Комментарии')
    date_upd = models.DateTimeField (auto_now_add=True, verbose_name=u'Дата обновления')
    
    class Meta:
        db_table = 'date_test'
        
    def __unicode__(self):
        return u"%s" % (self.name)

select 
    dt.id,
    dt.name,
    dt.bool_1,
    dt.date_reg,
    dt.bool_2,
    dt.error_msg,
    dt.comment,
    dt.date_upd,
    dt.date_upd - dt.date_reg as date_interval
from date_test dt where
    (dt.date_upd - dt.date_reg) < interval '432000' second
order by date_interval;