django：datediff sql查询吗？ [英] django: datediff sql queries?

问题描述

我正在尝试在Django中执行以下SQL：

I'm trying to do the equivalent of the following SQL in Django:

SELECT * FROM申请人WHERE date_out-date_in> = 1 AND date_out-date_in< = 6

SELECT * FROM applicant WHERE date_out - date_in >= 1 AND date_out - date_in <= 6

我可以作为RAW sql查询来执行此操作，但是在处理RawQuerySet而不是常规QuerySet对象时，这变得令人沮丧，因为我希望能够以便稍后在代码中对其进行过滤。

I can do this as a RAW sql query, but this is becoming frustrating in dealing with a RawQuerySet instead of a regular QuerySet object as I would like to be able to filter it later in the code.

推荐答案

您可以使用 extra（）方法并传入 where 关键字参数。 其中的值应为包含上面查询的SQL WHERE 子句的列表。我使用Postgresql 8.4进行了测试，这就是我的情况：

You can use the extra() method and pass in a where keyword argument. The value of where should be a list that contains the SQL WHERE clause of the query above. I tested this with Postgresql 8.4 and this is what it looked like in my case:

q = Applicant.objects.extra(where = ["""date_part('day', age(date_out, date_in)) >= 1 and
      date_part('day', age(date_out, date_in)) <= 6"""])

这将返回一个有效的 QuerySet 实例。

This will return you a valid QuerySet instance.

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