MongoDB - Field not showing in Aggregate - mongodb

Question

Query:
db.environments.aggregate(
[{$match:{customer:"CustomerName"}},
{$group:{_id:{environment: "$environment",
cpu_oversubscription:"$cpu_oversubscription",
memory_oversubscription:"$memory_oversubscription"}}} ])
When I run the query only the environment and the CPU_oversubcription fields are shown, the memory field is not shown.
This is the output I get:
[{"_id":{"environment":"V&B","cpu_oversubscription":1}}
When I run db.environments.find() I see all the fields
[{"_id":{"environment":"V&B","cpu_oversubscription":1,"memory_oversubscription":1,"customer":"CustomerName"}}
What is wrong with my query?
Edit: Exact Query
Environment.aggregate([{$match:{customer:req.query.customer}},{$group:{_id:{environment: "$environment",cpu_oversubscription:"$cpu_oversubscription",memory_oversubscription:"$memory_oversubscription",}}} ])
Exact Result of Query
{ "_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 } }
Exact result of db.environments.find() (1st result only)
{ "_id" : ObjectId("560a5139b56a71ea60890201"), "customer" : "CustomerName", "environment" : "1", "memory_oversubcription" : 1, "cpu_oversubscription" : 1 }

Answer 1

As #Yogesh said, you have a typo in your field in your data. This solve your problem.
Nevertheless, you do not need the aggregation framework for this query :
A find with a projection would be much more efficient :
db.environments.find({ "customer" : "CustomerName" },
{ _id : 0, "environment" : 1,
"memory_oversubscription" : 1,
"cpu_oversubscription" : 1
})
Result would be :
{
"environment" : "1",
"memory_oversubscription" : 1,
"cpu_oversubscription" : 1
}
If you really want the result under the _id field for some reasons, a $project whould be much better :
db.environments.aggregate([
{$match:{"customer" : "CustomerName"}},
{$project:
{_id :
{"environment" : "$environment",
"memory_oversubscription" : "$memory_oversubscription",
"cpu_oversubscription" : "$cpu_oversubscription"}
}
}
]);
Result :
{ "_id" : { "environment" : "1",
"memory_oversubscription" : 1,
"cpu_oversubscription" : 1 }
}
Doesn't make sense to me, but maybe it does for you :-).