Mongodb嵌套数组字段选择答案

【问题标题】：Mongo Nested array field selectionMongodb嵌套数组字段选择
【发布时间】：2019-12-06 14:37:52
【问题描述】：

下面是mongodb文档是这样的和这些嵌套数组字段选择：

对象：

    {
        "_id": {
            "$oid": "5de775b53ec85e73da2b6d8a"
        },
        "vpg_id": 2,
        "year": 2019,
        "am_data": {
            "822": {
                "am_name": "Unmanaged ",
                "no_of_mnths": 12,
                "total_invoice": 14476.15,
                "total_bv_invoice": 1840,
                "opp_won_onetime_amt": 0,
                "one_time_quota": 0,
                "recurring_quota": 200,
                "opp_won_rec_amt": 0,
                "avg_total_invoice": 1206.3458333333333,
                "avg_total_bv_invoice": 153.33333333333334,
                "avg_opp_won_onetime_amt": 0,
                "avg_one_time_quota": 0,
                "avg_opp_won_rec_amt": 0,
                "avg_recurring_quota": 16.666666666666668
            },
           "2155": {
                "am_name": "Daniel Schiralli",
                "no_of_mnths": 12,
                "total_invoice": 396814.66000000003,
                "total_bv_invoice": 577693.3200000001,
                "opp_won_onetime_amt": 4792.5,
                "one_time_quota": 14400,
                "recurring_quota": 4800,
                "opp_won_rec_amt": 345,
                "avg_total_invoice": 33067.888333333336,
                "avg_total_bv_invoice": 48141.11000000001,
                "avg_opp_won_onetime_amt": 399.375,
                "avg_one_time_quota": 1200,
                "avg_opp_won_rec_amt": 28.75,
                "avg_recurring_quota": 400
            }
        }
    }

我只想从所有 am_data 数组中选择 no_of_mnths 和 am_name。

钥匙 822 和 2155 是动态的。

它会改变，所以我不能直接在查询中给出它。我如何才能获得这些数据。不想

有什么帮助吗？

【问题讨论】：

标签： mongodb nested find

【解决方案1】：

您可以使用$objectToArray 运算符来摆脱动态键。

db.getCollection('Test').aggregate([

    { $project: {"keys": { "$objectToArray": "$$ROOT.am_data" }} },
    { $unwind : "$keys"},
    { $project: {"am_name":"$keys.v.am_name", "no_of_mnths":"$keys.v.no_of_mnths" } }
])

结果：

[{
    "_id" : ObjectId("5de775b53ec85e73da2b6d8a"),
    "am_name" : "Unmanaged ",
    "no_of_mnths" : 12
},
{
    "_id" : ObjectId("5de775b53ec85e73da2b6d8a"),
    "am_name" : "Daniel Schiralli",
    "no_of_mnths" : 12
}]

【讨论】：

【解决方案2】：

密钥不应该改变。根据您的描述，您需要调整架构，而不是am_data Object，它应该是一个数组。

{
     "_id": {
         "$oid": "5de775b53ec85e73da2b6d8a"
        },
     "vpg_id": 2,
     "year": 2019,
     "am_data": [
        {
            "id": "822",
             "am_name": "Unmanaged ",
             "no_of_mnths": 12,
             "total_invoice": 14476.15,
             "total_bv_invoice": 1840,
             "opp_won_onetime_amt": 0,
             "one_time_quota": 0,
             "recurring_quota": 200,
             "opp_won_rec_amt": 0,
             "avg_total_invoice": 1206.3458333333333,
             "avg_total_bv_invoice": 153.33333333333334,
             "avg_opp_won_onetime_amt": 0,
             "avg_one_time_quota": 0,
             "avg_opp_won_rec_amt": 0,
             "avg_recurring_quota": 16.666666666666668
        },
        {
            "id": "2155",
             "am_name": "Daniel Schiralli",
             "no_of_mnths": 12,
             "total_invoice": 396814.66000000003,
             "total_bv_invoice": 577693.3200000001,
             "opp_won_onetime_amt": 4792.5,
             "one_time_quota": 14400,
             "recurring_quota": 4800,
             "opp_won_rec_amt": 345,
             "avg_total_invoice": 33067.888333333336,
             "avg_total_bv_invoice": 48141.11000000001,
             "avg_opp_won_onetime_amt": 399.375,
             "avg_one_time_quota": 1200,
             "avg_opp_won_rec_amt": 28.75,
             "avg_recurring_quota": 400
        }
     ]
}

【讨论】：