如何创建一个查询来过滤一列等于另一列同一个表的行？

Question

假设我的模型看起来像:

class StockRequest(models.Model):
    amount_requested = models.PositiveIntegerField(null=True)
    amount_approved = models.PositiveIntegerField(null=True) 

有没有办法制作一个django查询,它会向我显示特定对象/行上的amount_requested和amount_approved之间存在某种关系的所有请求？

在SQL中,它将如下所示:

select * from stockrequest where amount_requested = amount_approved;

要么

select * from stockrequest where amount_requested = amount_approved;

在Django中,我不确定它是否可以完成,但我会想象下面的内容(注意:语法完全组成并且不起作用).

StockRequest.objects.filter(amount_requested="__amount_approved")

Answer 1

from django.db.models import F
StockRequest.objects.filter(amount_requested=F("amount_approved"))

http://docs.djangoproject.com/en/dev/topics/db/queries/#filters-can-reference-fields-on-the-model