Django ORM：按小时范围过滤 [英] Django ORM: filter by hour range

问题描述

我正在尝试为小时范围实施过滤器，它应该返回日期在hourA和hourB之间的记录（即：给我保存在16pm和18pm之间保存的记录）。
我的尝试：

I'm trying to implement a filter for hour range, it should returns records with a date between hourA and hourB (ie: "give me the records saved between 16pm and 18pm"). My attempts:

1）使用新的1.6 __ hour 过滤器和 __ in 或 __ range ：

1) Using new 1.6 __hour filter and __in or __range:

MyModel.objects.filter(date__hour__in=(16, 17, 18))
MyModel.objects.filter(date__hour__range=(16, 18))

上面的代码生成异常

2）使用Q对象：

hList = [Q(date__hour=h) for h in (16, 17, 18)]
MyModel.objects.filter(reduce(operator.or_, hList))

此版本有效，但效率很低，因为它在范围内的每一小时都会重复执行extract（）通过生成如下内容进行调用：

This version works, but is very inefficient, since for each hour in the range it repeats the extract() call by generating something like:

   where 
   extract(hour from date) = 16 or 
   extract(hour from date) = 17 or 
   extract(hour from date) = 18

正确的原始SQL应该是：

when instead the right raw SQL should be:

where extract(hour from date) in (16, 17, 18)

...如何在不依赖原始sql的情况下有效地按小时范围过滤？

…how can I filter by hour range in an effective manner, without relying on raw sql?

推荐答案

我设法通过以下方式解决了该问题：

I managed to solve the issue in this way:

    all_points = MyModel.objects.all()
    all_points.extra(where=['extract(hour from MyDateField) in (16, 17, 18)'])

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