Mongodb c#驱动Linq查询组by

我的mongodb文档结构如下:(每个文档创建每个Term Everyday)

{
    "_id" : ObjectId("53da1f0f12f0631d940f97a1"),
    "TermId" : "6cb28ca7-cc64-4b01-8dc5-b5f8d9fac9b5",
    "Term" : "priceless",
    "TotalCount" : 14,
    "date" : ISODate("2014-02-12T00:00:00.000Z"),
    "socialCounts" : [ 
        {
            "Name" : "twitter",
            "Count" : 3
        }, 
        {
            "Name" : "facebook",
            "Count" : 8
        },
        {
            "Name" : "Instagram",
            "Count" : 3
    ]
}

我需要得到

• 传入的每个termId的Totalcount的总和(grouby each termId and sum(Totalcount))。
• 传入的所有Term id的每个Social type计数之和。

我的方法目前只返回文档

public IQueryable<ReportingStats> GetReportingWallStats(List<string> terms, string[] sources, DateTime fr, DateTime to)
        {
            //var socialTypes = sources.ToBsonDocumentArray();
            try
            {
                var entities = from e in this.collection.AsQueryable<Collections.ReportingStats>()
                               where e.date >= fr && e.date <= to && terms.Contains(e.TermId) && e.TotalCount > 0
                               select e;
                var mongoQuery = ((MongoQueryable<ReportingStats>)entities).GetMongoQuery();
                var explain = entities.Explain();
                return entities;
            }
            catch (Exception ex)
            {
                Log.Error("Exception in  method GetReportingWallStats", ex);
                return null;
            }
        }

有人可以帮助我得到下面的结果

dictionaryItem(140年"Term1")

dictionaryItem(190年"Term2")

dictionaryItem(100年"Term3")

dictionaryItem(133年"Term4")

放入字典和

dictionaryItem(1440年"Facebook")

dictionaryItem(1640年"推特")

dictionaryItem(1940年"Instagram")

var map =
"function() {" +
"    for (var key in this) {" +
"        emit(key, { count : 1 });" +
"    }" +
"}";
var reduce =
"function(key, emits) {" +
"    total = 0;" +
"    for (var i in emits) {" +
"        total += emits[i].count;" +
"    }" +
"    return { count : total };" +
"}";
var mr = collection.MapReduce(map, reduce);
foreach (var document in mr.GetResults()) {
    Console.WriteLine(document.ToJson());
}