如何按日期对数据进行分组，并按月MongoDB进行比较

Question

我有如此大的CDR（呼叫详细报告）数据：

{
        "_id" : ObjectId("54eecc9a6c6852b9f0575bbb"),
        "msisdn" : "9818895866",
        "callType" : "NA",
        "duration" : 13.5,
        "charges" : 200,
        "traffic" : "Data",
        "Date" : ISODate("2014-02-15T12:15:42.535Z")
}
{
        "_id" : ObjectId("54eecc9a6c6852b9f0575bbc"),
        "msisdn" : "9818356561",
        "callType" : "STD",
        "duration" : 20.100000381469727,
        "charges" : 100,
        "traffic" : "Voice",
        "Date" : ISODate("2014-01-09T00:11:14.646Z")
}
{
        "_id" : ObjectId("54eecc9a6c6852b9f0575bbd"),
        "msisdn" : "9818173670",
        "callType" : "NA",
        "duration" : 19.399999618530273,
        "charges" : 300,
        "traffic" : "Data",
        "Date" : ISODate("2014-01-13T19:48:47.789Z")
}
{
        "_id" : ObjectId("54eecc9a6c6852b9f0575bbe"),
        "msisdn" : "9818719936",
        "callType" : "Local",
        "duration" : 9,
        "charges" : 350,
        "traffic" : "SMS",
        "Date" : ISODate("2014-03-02T10:51:29.846Z")
}
{
        "_id" : ObjectId("54eecc9a6c6852b9f0575bbf"),
        "msisdn" : "9818612562",
        "callType" : "STD",
        "duration" : 5.110000133514404,
        "charges" : 450,
        "traffic" : "Voice",
        "Date" : ISODate("2014-01-08T16:41:30.327Z")
}

我想显示使用TRAFFIC =“DATA”上个月持续时间的总和＆gt;当月持续时间总和* 2

仅显示更大的msisdn字段的总和

我试过这个

db.CDR.aggregate([ { $match : { traffic : "Data" }},{"$group" : {  
       "_id" : {  
            "Msisdn" : "$msisdn",  
            "Month" : "$date"  
       },  
       "Total Duration" : {  
            "$sum" : "$duration"  
       },  
       "Count" : {  
            "$sum" : 1  
       }  
  }  
 }])

显示持续时间的所有时间总和。

我想按月进行分组并比较每个月并仅显示更大的msisdn。