MongoDB 获取子文档 [英] MongoDB get SubDocument

问题描述

我想从 MongoDB 中的文档中检索子文档.我有以下文件:

I would like to retrieve a sub document from a document in MongoDB. I have the following document:

{
    "_id" : "10000",
    "password" : "password1",
    "name" : "customer1",
    "enabled" : true,
    "channels" : [ 
        {
            "id" : "10000-1",
            "name" : "cust1chan1",
            "enabled" : true
        }, 
        {
            "id" : "10000-2",
            "name" : "cust1chan2",
            "enabled" : true
        }
    ]
}

我想要的结果是:

{
    "id" : "10000-1",
    "name" : "cust1chan1",
    "enabled" : true
}

但是，到目前为止我能做的最好的事情是使用以下查询:

However, the best I can do so far is using the following query:

db.customer.find({"channels.id" : "10000-1"}, {"channels.$" : 1, "_id" : 0})

但这给了我以下结果:

{
    "channels" : [ 
        {
            "id" : "10000-1",
            "name" : "cust1chan1",
            "enabled" : true
        }
    ]
}

有谁知道是否可以编写一个查询来给出我想要的结果?任何帮助将不胜感激.

Does anyone know if it is possible to write a query that will give me my desired result? Any help would be much appreciated.

推荐答案

您可以使用聚合框架来实现.查询将类似于:

You can do it with Aggregation Framework. Query will be something like :

db.customer.aggregate([
    {$unwind : "$channels"},
    {$match : {"channels.id" : "10000-1"}},
    {$project : {_id : 0, 
                 id : "$channels.id", 
                 name : "$channels.name", 
                 enabled : "$channels.enabled"}}
])

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