python - 从 Django DateTimeField 中查找相对日期

Question

型号:

class MyClass(models.Model):
    car = models.ForeignKey(Car)
    date = models.DateTimeField(auto_now=True, auto_now_add=True)

sql:

SELECT car FROM cars_myclass WHERE date < NOW() - INTERVAL 1 DAY;

所以，我有类似的东西:

cars = MyClass.objects.all().filter(date < ... )

但是如何编写 NOW() - INTERVAL 1 DAY 呢？谢谢。

Answer 1

通过 datetime.datetime对象(减去 datetime.timedelta 对象):

>>> import datetime
>>> now = datetime.datetime.now()
>>> now
datetime.datetime(2013, 12, 29, 21, 54, 30, 836000)
>>> now - datetime.timedelta(days=1)
datetime.datetime(2013, 12, 28, 21, 54, 30, 836000)

---

import datetime

cars = MyClass.objects.filter(date__lt=datetime.datetime.now() - datetime.timedelta(days=1))

---

更新 Mikko Ohtamaa 的评论:

同时为了避免时区问题，我建议使用 timezone.now()而不是 datetime.datetime.now()(自 Django 1.4 起可用)

import datetime
from django.utils import timezone

cars = MyClass.objects.filter(date__lt=timezone.now() - datetime.timedelta(days=1))