MongoDB-未在聚合中显示的字段

查询：

db.environments.aggregate(
[{$match:{customer:"CustomerName"}},
{$group:{_id:{environment: "$environment",
cpu_oversubscription:"$cpu_oversubscription",
memory_oversubscription:"$memory_oversubscription"}}} ])

当我运行查询时，只显示环境和CPU_Oversubscription字段，而不显示memory字段

这是我得到的输出：

[{"_id":{"environment":"V&B","cpu_oversubscription":1}}

当我运行

db.environments.find（）

时，我会看到所有字段

[{"_id":{"environment":"V&B","cpu_oversubscription":1,"memory_oversubscription":1,"customer":"CustomerName"}}

我的问题出了什么问题

编辑：精确查询

Environment.aggregate([{$match:{customer:req.query.customer}},{$group:{_id:{environment: "$environment",cpu_oversubscription:"$cpu_oversubscription",memory_oversubscription:"$memory_oversubscription",}}} ])

{ "_id" : { "environment" : "1", "cpu_oversubscription" : 1 } }
{ "_id" : { "environment" : "2", "cpu_oversubscription" : 4 } }
{ "_id" : { "environment" : "3", "cpu_oversubscription" : 4 } }
{ "_id" : { "environment" : "4", "cpu_oversubscription" : 4 } }
{ "_id" : { "environment" : "5", "cpu_oversubscription" : 4 } }
{ "_id" : { "environment" : "6", "cpu_oversubscription" : 1 } }
{ "_id" : { "environment" : "7", "cpu_oversubscription" : 1 } }
{ "_id" : { "environment" : "8", "cpu_oversubscription" : 1 } }
{ "_id" : { "environment" : "9", "cpu_oversubscription" : 4 } }
{ "_id" : { "environment" : "10", "cpu_oversubscription" : 4 } }

查询的准确结果

Environment.aggregate([{$match:{customer:req.query.customer}},{$group:{_id:{environment: "$environment",cpu_oversubscription:"$cpu_oversubscription",memory_oversubscription:"$memory_oversubscription",}}} ])

{ "_id" : { "environment" : "1", "cpu_oversubscription" : 1 } }
{ "_id" : { "environment" : "2", "cpu_oversubscription" : 4 } }
{ "_id" : { "environment" : "3", "cpu_oversubscription" : 4 } }
{ "_id" : { "environment" : "4", "cpu_oversubscription" : 4 } }
{ "_id" : { "environment" : "5", "cpu_oversubscription" : 4 } }
{ "_id" : { "environment" : "6", "cpu_oversubscription" : 1 } }
{ "_id" : { "environment" : "7", "cpu_oversubscription" : 1 } }
{ "_id" : { "environment" : "8", "cpu_oversubscription" : 1 } }
{ "_id" : { "environment" : "9", "cpu_oversubscription" : 4 } }
{ "_id" : { "environment" : "10", "cpu_oversubscription" : 4 } }

db.environments.find（）的精确结果（仅第一个结果）

---

正如@Yogesh所说，您的数据中的字段有一个输入错误。这就解决了你的问题

但是，此查询不需要聚合框架： 带有投影的查找将更加高效：

db.environments.find({ "customer" : "CustomerName" }, 
                     { _id : 0, "environment" : 1,
                       "memory_oversubscription" : 1, 
                       "cpu_oversubscription" : 1
                     })

结果将是：

{ 
  "environment" : "1", 
  "memory_oversubscription" : 1,
  "cpu_oversubscription" : 1 
}

如果出于某些原因，您确实希望在_id字段下获得结果，那么$project会更好：

db.environments.aggregate([
  {$match:{"customer" : "CustomerName"}},
  {$project: 
    {_id : 
      {"environment" : "$environment",
       "memory_oversubscription" : "$memory_oversubscription", 
       "cpu_oversubscription" : "$cpu_oversubscription"}
    }
  }
]);

结果:

{ "_id" : { "environment" : "1", 
            "memory_oversubscription" : 1, 
            "cpu_oversubscription" : 1 } 
}

---

这对我来说没有意义，但也许对你有意义：-）。

这里的数据样本正确吗？所有内容都在

\u id

下，聚合中的任何字段（看起来是基于我提出的问题，实际上是我自己回答的问题）都没有前缀

\u id

，如

{“$group”：{“\u id”：{“environment”：“$\u id.environment”}

。主要注意到这不是前面问题中提出的结构。因此，我认为你在帖子中犯了一个错误。这个问题是正确的，但我不认为这有什么意义，因为你最终没有对任何东西进行分组。如果你不使用这些运算符中的任何一个：，我想一个简单的查找就可以了。为什么cpu超订阅会显示，而内存超订阅不会显示？你能添加一个示例文档并告诉我们你的要求吗？@CMS看起来你把

内存超订阅

错放到

内存超订阅