Django按日期排序，但“无"最后? [英] Django Order By Date, but have "None" at end?

问题描述

我有一个工单模型，其中有一个字段用于显示何时需要工单.要获取工单列表以及早期需要的工单列表，我会这样做:

I have a model of work orders, with a field for when the work order is required by. To get a list of work orders, with those that are required early, I do this:

wo = Work_Order.objects.order_by('dateWORequired')

这很好用，但前提是该字段中确实有值.如果没有必需的日期，则值为 None.然后，工单列表的顶部是所有None，然后是其余工单以正确的顺序排列.

This works nicely, but ONLY if there is actually a value in that field. If there is no required date, then the value is None. Then, the list of work orders has all the None's at the top, and then the remaining work orders in proper order.

我怎样才能得到底部的None?

How can I get the None's at the bottom?

推荐答案

q = q.extra(select={
        'date_is_null': 'dateWORequired IS NULL',
    },
    order_by=['date_is_null','dateWORequired'],
)

您可能需要在 order_by 部分中的 date_is_null 之前添加 -，但这就是您可以控制行为的方式.

You might need a - before the date_is_null in the order_by portion, but that's how you can control the behavior.

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