标签: aggregation-framework

我有以下文件：

{
    _id     : 1,

    key1    : {
                  samekeyA : "value1",
                  samekeyB : "value2"
              },

    key2 :    {
                  samekeyA : "value3",
                  samekeyB : "value4"
              },

    key3 :    {
                  samekeyA : "value5",
                  samekeyB : "value6"
              }  
}

以上; key1,key2并被key3用来证明我不知道完整的密钥，除了它的前缀；但内在的钥匙samekeyA和samekeyB我知道的那些。我需要查询，例如：db.coll.find({"key*.samekeyA":"value1"})。

我认为没有一种 mongo 方式 - 正则表达式键查询？ - 来实现这一点，所以有什么想法吗？我应该改造我的文档-tree-吗？

鉴于以下文件：

{
        "_id" : ObjectId("53cd79bb300ccae6b3904402"),
        "name" : "test product",
        "sku" : "product-1",
        "price" : 35,
        "cost" : 12,
        "max_cpc" : 100,
        "price_in_cents" : 3500,
        "cost_in_cents" : 1200,
        "max_cpc_in_cents" : 10000,
        "clicks" : [
                {
                        "date" : ISODate("2014-04-25T00:00:00Z"),
                        "clicks" : 2,
                        "channel" : "google",
                        "campaign" : "12345687",
                        "group" : "987654321"
                },
                {
                        "date" : ISODate("2014-04-25T00:00:00Z"),
                        "clicks" : 3,
                        "channel" : "google",
                        "campaign" : "8675309",
                        "group" : "9035768"
                },
                {
                        "date" : ISODate("2014-04-24T00:00:00Z"),
                        "clicks" : 1,
                        "channel" : "google",
                        "campaign" : "8675309", …

我需要计算一组文件的加权平均值.每个文档在单独的字段中包含权重和值.这是一个例子:我有两个代表销售交易的文件.

{
    quantity : 3,
    price : 2
}

{
    quantity : 9,
    price : 6
}

我想找到这两笔交易的平均价格.这是加权平均值,其中权重是数量,价值是价格.这可以通过计算得出

AveragePrice = (3 * 2 + 9 * 6 ) / (3 + 9).

如何使用聚合框架执行此计算？

假设我有以下 MongoDB 文档。

{
(...)
"services": {
    "TCP80": {
      "data": [{
          "status": 1,
          "delay": 3.87,
          "ts": 1308056460
        },{
          "status": 1,
          "delay": 2.83,
          "ts": 1308058080
        },{
          "status": 1,
          "delay": 5.77,
          "ts": 1308060720
        }]
    }
}}

我希望检索“数据”数组中“ts”值大于“1308056460”的所有条目。因此，预期的结果是，

[
        {
          "status": 1,
          "delay": 2.83,
          "ts": 1308058080
        },{
          "status": 1,
          "delay": 5.77,
          "ts": 1308060720
        }
]

一种方法是使用 MongoDB 聚合函数。

db.test.aggregate(
   {$match : {}},
   {$unwind: "$services.TCP80.data"},
   {$match: {"services.TCP80.data.ts": {$gte: 1308060720}}}
 );

另一种方法是将整个数据数组检索到中间层（node.js 应用程序）并运行循环以过滤掉我想要的值。

撇开实现的简单性不谈，哪种方法更有效或产生更快的结果？为什么？

我在 mongoDB 中有一个类似于下面的大数据集

我想在 MongoDB 中运行一个聚合，它相当于这个 SQL：

SELECT SUM(cores) from machines 
WHERE idc='AMS' AND cluster='1' AND type='Physical';

我如何在 MongoDB 中进行此操作？

[
    {
        "_id" : "55d5dc40281077b6d8af1bfa",
        "hostname" : "x",
        "domain" : "domain",
        "description" : "VMWare ESXi 5",
        "cluster" : "1",
        "type" : "Physical",
        "os" : "EXSi",
        "idc" : "AMS",
        "environment" : "DR",
        "deviceclass" : "host",
        "cores" : "64",
        "memory" : "256",
        "mounts" : [ ],
        "roles" : [
                "ESX-HOST"
        ],
        "ipset" : {
                "backnet" : "1"
        },
        "frontnet" : [ ], …

我有mongo类型的文件-

{
    "_id" : ObjectId("77f02ee61df85c423b6a4e79"),
    "client" : "1"
    "type" : "type1",
    "hierarchy" : "hier1",
    "creationDate" : ISODate("2015-09-09T13:06:44Z"),
    "model" : "m1"
},
{
    "_id" : ObjectId("77f02ee61df85c423b6a4e80"),
    "client" : "1"
    "type" : "type1",
    "hierarchy" : "hier1",
    "creationDate" : ISODate("2015-09-10T14:06:44Z"),
    "model" : "m2"
},
{
    "_id" : ObjectId("77f02ee61df85c423b6a4e81"),
    "client" : "1"
    "type" : "type1",
    "hierarchy" : "hier2",
    "creationDate" : ISODate("2015-09-10T13:06:44Z"),
    "model" : "m3"
},
{
    "_id" : ObjectId("77f02ee61df85c423b6a4e82"),
    "client" : "2"
    "type" : "type2",
    "hierarchy" : "hier2",
    "creationDate" : ISODate("2015-09-10T14:06:44Z"),
    "model" …

My main object looks like this:

{
"_id" : ObjectId("56eb0a06560fd7047318465a"),
 ...
"intervalAbsenceDates" : [
    DBRef("ScheduleIntervalContainer", ObjectId("56eb0a06560fd7047318463b")),
    DBRef("ScheduleIntervalContainer", ObjectId("56eb0a05560fd70473184467")),
    DBRef("ScheduleIntervalContainer", ObjectId("56eb0a05560fd70473184468")),
    DBRef("ScheduleIntervalContainer", ObjectId("56eb0a05560fd70473184469")),

An embedded ScheduleIntervalContainer object looks like this:

{
"_id" : ObjectId("56eb0a06560fd7047318463b"),
"end" : ISODate("2022-08-23T07:06:00Z"),
"available" : true,
"confirmation" : true,
"start" : ISODate("2022-08-19T09:33:00Z")
}

Now I will query all ScheduleIntervalContainers where start and end is in a range. I have tried a lot but I not even can query one ScheduleIntervalContainer by id. This is my approach:

db.InstitutionUserConnection.find( …

在我的查询中，concat关键字不起作用，它返回null。

这是查询：-

db.leads.aggregate([
{$project:{
    _id:0,
    status:1,
    stage:1,
    "todo.title":1,
    created:{
        day:{$substr:["$createdOn",8,2]},
        month:{$substr:["$createdOn",5,2]},
        year:{$substr:["$createdOn",0,4]}
        },
     myDate:{$concat:["$created.day","-","$created.month","-","$created.day"]}
         //----above $concat is not working-----//
         //--i want that `myDate` should be "12-09-2016"----//
    }
  }

])

这是查询输出：

{
    "stage" : "Prospect",
    "todo" : [],
    "status" : "OPEN",
    "created" : {
        "day" : "12",
        "month" : "09",
        "year" : "2016"
    },
    "myDate" : null

   //--here i want that `myDate` should be "12-09-2016"----//
}

在mongodb 中将createdOn字段数据存储为Date类型，即