C#代码利用MongoDB中Group聚合函数查询

例子：

public static void getUserRFM(DateTime beginTime, DateTime endTime)
        {
            MongoDatabase mongoDB = getConnection();

            //会员消费明细的实体类
            List<Ky_Shopplist> shopplist = new List<Ky_Shopplist>();

            //获得Ky_shopplist集合
            MongoCollection col = mongoDB.GetCollection("Ky_Shopplist");

            //获得Ky_UserRFM的集合
            MongoCollection colRFM = mongoDB.GetCollection("Ky_UserRFM");

            //删除Ky_UserRFM集合中所有的数据
            colRFM.RemoveAll();

            //定义获取“buyTime”相关的查询条件
            var query = Query.And(Query.GTE("buyTime", beginTime.ToString("yyyy-MM-dd HH:mm:ss")), Query.LTE("buyTime", endTime.ToString("yyyy-MM-dd HH:mm:ss")));

            //var result = col.FindAs<Ky_Shopplist>(query).ToList();
            //var result_all = col.FindAllAs<Ky_Shopplist>().ToList();

            //会员RFM值实体类
            List<Ky_UserRFM> userRFMlist = new List<Ky_UserRFM>();

            //GroupBy的字段
            GroupByBuilder groupbyBuilder = new GroupByBuilder(new string[] { "userId" });

            #region 计算会员R值

            try
            {

                //计算每组UserId的最大时间
                Dictionary<string, string> dic_R = new Dictionary<string, string>();
                dic_R["time"] = DateTime.Now.ToString();
                var result_R = col.Group(query, groupbyBuilder, BsonDocument.Create(dic_R),
                                    BsonJavaScript.Create("function(obj,prev){if(prev.time>obj.buyTime){prev.time=obj.buyTime;}}"),
                                    BsonJavaScript.Create("function(obj){ obj.btime=obj.time;delete obj.time; }")).ToList();

                 if (result_R.Count != 0)
                 {
                    //计算出会员距今最近的消费时间和最远的消费时间
                    DateTime Mintime = DateTime.Now;
                    DateTime Maxtime = DateTime.Now;
                    for (int i = 1; i < result_R.Count; i++)
                    {
                        if (i == 1)
                        {
                            Maxtime = Convert.ToDateTime(result_R[i]["btime"]) > Convert.ToDateTime(result_R[0]["btime"]) ? Convert.ToDateTime(result_R[i]["btime"]) : Convert.ToDateTime(result_R[0]["btime"]);

                            Mintime = Convert.ToDateTime(result_R[i]["btime"]) < Convert.ToDateTime(result_R[0]["btime"]) ? Convert.ToDateTime(result_R[i]["btime"]) : Convert.ToDateTime(result_R[0]["btime"]);

                        }
                        else
                        {
                            Maxtime = Maxtime > Convert.ToDateTime(result_R[i]["btime"]) ? Maxtime : Convert.ToDateTime(result_R[i]["btime"]);

                            Mintime = Mintime < Convert.ToDateTime(result_R[i]["btime"]) ? Mintime : Convert.ToDateTime(result_R[i]["btime"]);
                        }
                    }

                    double R_interval = 0.0;
                    R_interval = (Maxtime - Mintime).TotalSeconds / 5;

                    //计算会员R值
                    for (int i = 0; i < result_R.Count; i++)
                    {
                        DateTime dtTime = Convert.ToDateTime(result_R[i]["btime"]);
                        string userId = result_R[i]["userId"].ToString();
                        string struser_R = "0";

                        if (dtTime >= Mintime && dtTime <= Mintime.AddSeconds(R_interval))
                        {
                            struser_R = "1";
                        }
                        if (dtTime >= Mintime.AddSeconds(R_interval) && dtTime <= Mintime.AddSeconds(R_interval * 2))
                        {
                            struser_R = "2";
                        }
                        if (dtTime >= Mintime.AddSeconds(R_interval * 2) && dtTime <= Mintime.AddSeconds(R_interval * 3))
                        {
                            struser_R = "3";
                        }
                        if (dtTime >= Mintime.AddSeconds(R_interval * 3) && dtTime <= Mintime.AddSeconds(R_interval * 4))
                        {
                            struser_R = "4";
                        }
                        if (dtTime >= Mintime.AddSeconds(R_interval * 4) && dtTime <= Maxtime)
                        {
                            struser_R = "5";
                        }

                        Ky_UserRFM userRFM = new Ky_UserRFM();

                        userRFM.user_R = struser_R;
                        userRFM.user_F = "0";
                        userRFM.user_M = "0";

                        userRFM.user_Tagid = "";
                        userRFM.user_Id = userId;
                        userRFM.current_Time = DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss");

                        userRFMlist.Add(userRFM);
                    }

                    //批量插入会员RFM表
                    colRFM.InsertBatch(typeof(Ky_UserRFM), userRFMlist);
                }
            }
            catch (Exception ex)
            {
                throw;
            }

            #endregion

            #region 计算会员F值

            try
            {

　　　　　　//计算每组UserId的次数

                Dictionary<string, int> dic_F = new Dictionary<string, int>();
                dic_F["num"] = 0;
                var result_F = col.Group(query, groupbyBuilder, BsonDocument.Create(dic_F),
                                               BsonJavaScript.Create("function(doc,prev){prev.num++;}"),
                                               BsonJavaScript.Create("function(doc){ doc.count=doc.num;delete doc.num; }")).ToList();

                if (result_F.Count != 0)
                {
                    //计算出会员最大消费频率和最小消费频率
                    double Maxcount = 0;
                    double Mincount = 0;
                    for (int i = 1; i < result_F.Count; i++)
                    {
                        if (i == 1)
                        {
                            Maxcount = Convert.ToInt32(result_F[i]["count"]) > Convert.ToInt32(result_F[0]["count"]) ? Convert.ToInt32(result_F[i]["count"]) : Convert.ToInt32(result_F[0]["count"]);

                            Mincount = Convert.ToInt32(result_F[i]["count"]) < Convert.ToInt32(result_F[0]["count"]) ? Convert.ToInt32(result_F[i]["count"]) : Convert.ToInt32(result_F[0]["count"]);
                        }
                        else
                        {
                            Maxcount = Maxcount > Convert.ToInt32(result_F[i]["count"]) ? Maxcount : Convert.ToInt32(result_F[i]["count"]);

                            Mincount = Mincount < Convert.ToInt32(result_F[i]["count"]) ? Mincount : Convert.ToInt32(result_F[i]["count"]);
                        }
                    }

                    double F_inteval = 0.0;
                    F_inteval = (Maxcount - Mincount) / 5;

                    //计算每个会员的F值
                    for (int i = 1; i < result_F.Count; i++)
                    {
                        string strUserid = result_F[i]["userId"].ToString();
                        int icount = Convert.ToInt32(result_F[i]["count"]);
                        string strUser_F = "0";

                        if (icount >= Mincount && icount <= F_inteval)
                        {
                            strUser_F = "1";
                        }
                        if (icount >= F_inteval && icount <= (F_inteval * 2))
                        {
                            strUser_F = "2";
                        }
                        if (icount >= (F_inteval * 2) && icount <= (F_inteval * 3))
                        {
                            strUser_F = "3";
                        }
                        if (icount >= (F_inteval * 3) && icount <= (F_inteval * 4))
                        {
                            strUser_F = "4";
                        }
                        if (icount >= (F_inteval * 4) && icount <= Maxcount)
                        {
                            strUser_F = "5";
                        }

                        //执行更新操作
                        var query_F = Query.EQ("user_Id", strUserid);
                        var update_F = new UpdateDocument { { "$set", new QueryDocument { { "user_F", strUser_F } } } };

                        colRFM.Update(query_F, update_F);
                    }
                }
            }
            catch (Exception ex)
            {
                throw;
            }

            #endregion

            #region 计算会员M值

            try
            {

　　　　　　//计算每组UserId中price（金额）的总和
                //var query_price = new QueryDocument{{"price",true}};
                //var update_price = new UpdateDocument{{"price",BsonType.Double}};
                //colRFM.Update(query_price, update_price);

                Dictionary<string, double> dic_M = new Dictionary<string, double>();
                dic_M["msum"] = 0.0;
                var result_M = col.Group(query, groupbyBuilder, BsonDocument.Create(dic_M),
                                                BsonJavaScript.Create("function(obj,prev){prev.msum += obj.price;}"),
                                                BsonJavaScript.Create("function(obj){obj.sum=obj.msum;delete obj.sum;}")).ToList();

                if (result_M.Count != 0)
                {
                    //计算出会员最大的消费金额和最小的消费金额
                    double Maxsum = 0.0;
                    double Minsum = 0.0;
                    for (int i = 1; i < result_M.Count; i++)
                    {
                        if (i == 1)
                        {
                            Maxsum = Convert.ToDouble(result_M[i]["msum"]) > Convert.ToDouble(result_M[0]["msum"]) ? Convert.ToDouble(result_M[i]["msum"]) : Convert.ToDouble(result_M[0]["msum"]);

                            Minsum = Convert.ToDouble(result_M[i]["msum"]) < Convert.ToDouble(result_M[0]["msum"]) ? Convert.ToDouble(result_M[i]["msum"]) : Convert.ToDouble(result_M[0]["msum"]);
                        }
                        else
                        {
                            Maxsum = Maxsum > Convert.ToDouble(result_M[i]["msum"]) ? Maxsum : Convert.ToDouble(result_M[i]["msum"]);

                            Minsum = Minsum < Convert.ToDouble(result_M[i]["msum"]) ? Minsum : Convert.ToDouble(result_M[i]["msum"]);
                        }
                    }

                    double M_interval = 0.0;
                    M_interval = (Maxsum - Minsum) / 5;

                    //计算每个会员的M值
                    for (int i = 0; i < result_M.Count; i++)
                    {
                        string strUserId = result_M[i]["userId"].ToString();
                        double dsum = Convert.ToDouble(result_M[i]["msum"]);

                        string struser_M = "0";
                        if (dsum >= Minsum && dsum <= M_interval)
                        {
                            struser_M = "1";
                        }
                        if (dsum >= M_interval && dsum <= (M_interval * 2))
                        {
                            struser_M = "2";
                        }
                        if (dsum >= (M_interval * 2) && dsum <= (M_interval * 3))
                        {
                            struser_M = "3";
                        }
                        if (dsum >= (M_interval * 3) && dsum <= (M_interval * 4))
                        {
                            struser_M = "4";
                        }
                        if (dsum >= (M_interval * 4) && dsum <= Maxsum)
                        {
                            struser_M = "5";
                        }

                        //执行更新操作
                        var query_M = Query.EQ("user_Id", strUserId);
                        var update_M = new UpdateDocument { { "$set", new QueryDocument { { "user_M", struser_M } } } };

                        colRFM.Update(query_M, update_M);
                    }
                }
            }
            catch (Exception ex)
            {
                throw;
            }

            #endregion

        }