Mongodb 排序内部数组 [英] Mongodb sort inner array

问题描述

我一直在寻找一段时间，但似乎无法对内部数组进行排序并将其保存在我目前正在使用的文档中.

I've been looking for a while now and can't seem to sort an inner array and keep that in the doc that I'm currently working with.

{
    "service": {
        "apps": {
            "updates": [
              {
                "n" : 1
                "date": ISODate("2012-03-10T16:15:00Z")
              },
              {
                "n" : 2
                "date": ISODate("2012-01-10T16:15:00Z")
              },
              {
                "n" : 5
                "date": ISODate("2012-07-10T16:15:00Z")
              }
            ]
        }
     }
 }

所以我想保留要作为服务返回的项目，但对我的更新数组进行排序.到目前为止，我拥有的外壳:

So I want to keep the item to be returned as the service, but have my updates array sorted. So far with the shell I have:

db.servers.aggregate(
        {$unwind:'$service'},
        {$project:{'service.apps':1}},
        {$unwind:'$service.apps'}, 
        {$project: {'service.apps.updates':1}}, 
        {$sort:{'service.apps.updates.date':1}});

有人认为他们可以提供帮助吗?

Anyone think they can help on this?

推荐答案

您可以通过 $unwind 对 updates 数组进行排序，并按 date，然后 $group 使用排序顺序将它们在 _id 上重新组合在一起.

You can do this by $unwinding the updates array, sorting the resulting docs by date, and then $grouping them back together on _id using the sorted order.

db.servers.aggregate(
    {$unwind: '$service.apps.updates'}, 
    {$sort: {'service.apps.updates.date': 1}}, 
    {$group: {_id: '$_id', 'updates': {$push: '$service.apps.updates'}}}, 
    {$project: {'service.apps.updates': '$updates'}})

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