总计 $project 中的新 Date() [英] new Date() in aggregate $project

问题描述

对于我的一个集合，它必须保留 unix 时间戳而不是 isodate，我通常将时间戳转换为 new Date(unix_timestamp).

For one of my collections, which must remain unix timestamp instead of isodate, I usually convert the timestamp with new Date(unix_timestamp).

现在我需要聚合中的 new Date(ts).(例子是PHP)

Now I need the new Date(ts) in an aggregation. (the example is in PHP)

'$project' =>数组 ('day' => '$new Date(ts)', ...

'$project' => array ( 'day' => '$new Date(ts)', ...

'$group' =>数组(_id"=>数组('day' =>'$day)', ...),...

'$group' => array ( "_id" => array('day' => '$day)', ...),...

没有到达结果.字段日"结果完全丢失了.

does not arrive in the results. The field "day" in the result is missing entirely.

如何在聚合中进行转换?

How to get this converted within the aggregation?

推荐答案

为了能够从文档中添加时间戳字段，您可以这样做，给定:

to be able to add a timestamp field from the document, you can do this, given:

{"ts": 1400512120100}

聚合为日期:

db.foo.aggregate({
   $project: {
       date: { $add: [new Date(0), "$ts"] }
   }
})

这篇关于总计 $project 中的新 Date()的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！