Linq分组取分组中的最大值，并且拿到最大值对应的id

Linq分组取分组中的最大值，并且拿到最大值对应的id

第一种分组方式：唯一键：手机号码；

            List<PhoneCallCTIPushData> phoneCallCTIPushDatas = new List<PhoneCallCTIPushData>();

            PhoneCallCTIPushData phoneCallCTIPushData1 = new PhoneCallCTIPushData() { };
            phoneCallCTIPushData1.Id = 119;
            phoneCallCTIPushData1.MobilePhoneNum = "13059310001";
            phoneCallCTIPushData1.CreateDate = Convert.ToDateTime("2022-10-01");
            phoneCallCTIPushDatas.Add(phoneCallCTIPushData1);

            PhoneCallCTIPushData phoneCallCTIPushData2 = new PhoneCallCTIPushData() { };
            phoneCallCTIPushData2.Id = 1299;
            phoneCallCTIPushData2.MobilePhoneNum = "13059310001";
            phoneCallCTIPushData2.CreateDate = Convert.ToDateTime("2022-11-02");
            phoneCallCTIPushDatas.Add(phoneCallCTIPushData2);

            PhoneCallCTIPushData phoneCallCTIPushData13 = new PhoneCallCTIPushData() { };
            phoneCallCTIPushData13.Id = 99;
            phoneCallCTIPushData13.MobilePhoneNum = "13059310001";
            phoneCallCTIPushData13.CreateDate = Convert.ToDateTime("2022-12-02");
            phoneCallCTIPushDatas.Add(phoneCallCTIPushData13);

            PhoneCallCTIPushData phoneCallCTIPushData3 = new PhoneCallCTIPushData() { };
            phoneCallCTIPushData3.Id = 3;
            phoneCallCTIPushData3.MobilePhoneNum = "13059310002";
            phoneCallCTIPushData3.CreateDate = Convert.ToDateTime("2022-10-03");
            phoneCallCTIPushDatas.Add(phoneCallCTIPushData3);

            PhoneCallCTIPushData phoneCallCTIPushData4 = new PhoneCallCTIPushData() { };
            phoneCallCTIPushData4.Id = 4;
            phoneCallCTIPushData4.MobilePhoneNum = "13059310002";
            phoneCallCTIPushData4.CreateDate = Convert.ToDateTime("2022-10-04");
            phoneCallCTIPushDatas.Add(phoneCallCTIPushData4);

            //第一轮筛选：筛选出最新日期的手机号对应的数据
            var linqResult = from t1 in phoneCallCTIPushDatas
                             group t1 by t1.MobilePhoneNum into groupTable
                             select new
                             {
                                 CreateDate2 = groupTable.Max(x => x.CreateDate),
                                 MobilePhoneNum2 = groupTable.Key
                             };

            List<PhoneCallCTIPushData> phoneCallCTIPushDatas2 = new List<PhoneCallCTIPushData>();
            Console.WriteLine("打印准备要筛选的：");
            foreach (var item in linqResult)
            {
                //第二轮筛选：匹配最新日期的手机号对应的id值
                PhoneCallCTIPushData phoneCallCTIPushData = phoneCallCTIPushDatas
                .Where(aa => aa.CreateDate == item.CreateDate2 && aa.MobilePhoneNum == item.MobilePhoneNum2)
                .OrderByDescending(bb => bb.Id).FirstOrDefault();

                phoneCallCTIPushDatas2.Add(phoneCallCTIPushData);
                Console.WriteLine(item.CreateDate2 + " " + item.MobilePhoneNum2 + " ");
            }
            Console.WriteLine();
            Console.WriteLine("打印结果：");
            foreach (var item in phoneCallCTIPushDatas2)
            {
                Console.WriteLine(item.Id + " " + item.MobilePhoneNum + " " + item.CreateDate);
            }
            Console.ReadKey();

 

 第二种分组方式：组合唯一键：通话日期+手机号码；

            List<PhoneCallCTIPushData> phoneCallCTIPushDatasAll = new List<PhoneCallCTIPushData>();

            PhoneCallCTIPushData phoneCallCTIPushData1 = new PhoneCallCTIPushData() { };
            phoneCallCTIPushData1.Id = 11;
            phoneCallCTIPushData1.CallDay = Convert.ToDateTime("2022-10-01");
            phoneCallCTIPushData1.MobilePhoneNum = "13059310001";
            phoneCallCTIPushData1.CreateDate = Convert.ToDateTime("2022-09-01");
            phoneCallCTIPushDatasAll.Add(phoneCallCTIPushData1);

            PhoneCallCTIPushData phoneCallCTIPushData2 = new PhoneCallCTIPushData() { };
            phoneCallCTIPushData2.Id = 12;
            phoneCallCTIPushData2.CallDay = Convert.ToDateTime("2022-10-01");
            phoneCallCTIPushData2.MobilePhoneNum = "13059310001";
            phoneCallCTIPushData2.CreateDate = Convert.ToDateTime("2022-09-05");
            phoneCallCTIPushDatasAll.Add(phoneCallCTIPushData2);

            PhoneCallCTIPushData phoneCallCTIPushData13 = new PhoneCallCTIPushData() { };
            phoneCallCTIPushData13.Id = 13;
            phoneCallCTIPushData13.CallDay = Convert.ToDateTime("2022-10-02");
            phoneCallCTIPushData13.MobilePhoneNum = "13059310001";
            phoneCallCTIPushData13.CreateDate = Convert.ToDateTime("2022-09-06");
            phoneCallCTIPushDatasAll.Add(phoneCallCTIPushData13);

            PhoneCallCTIPushData phoneCallCTIPushData14 = new PhoneCallCTIPushData() { };
            phoneCallCTIPushData14.Id = 14;
            phoneCallCTIPushData14.CallDay = Convert.ToDateTime("2022-10-02");
            phoneCallCTIPushData14.MobilePhoneNum = "13059310001";
            phoneCallCTIPushData14.CreateDate = Convert.ToDateTime("2022-09-02");
            phoneCallCTIPushDatasAll.Add(phoneCallCTIPushData14);

            //--------------------------------------------------------------------------

            PhoneCallCTIPushData phoneCallCTIPushData3 = new PhoneCallCTIPushData() { };
            phoneCallCTIPushData3.Id = 15;
            phoneCallCTIPushData3.CallDay = Convert.ToDateTime("2022-10-01");
            phoneCallCTIPushData3.MobilePhoneNum = "13059310002";
            phoneCallCTIPushData3.CreateDate = Convert.ToDateTime("2022-09-03");
            phoneCallCTIPushDatasAll.Add(phoneCallCTIPushData3);

            PhoneCallCTIPushData phoneCallCTIPushData4 = new PhoneCallCTIPushData() { };
            phoneCallCTIPushData4.Id = 16;
            phoneCallCTIPushData4.CallDay = Convert.ToDateTime("2022-10-01");
            phoneCallCTIPushData4.MobilePhoneNum = "13059310002";
            phoneCallCTIPushData4.CreateDate = Convert.ToDateTime("2022-09-04");
            phoneCallCTIPushDatasAll.Add(phoneCallCTIPushData4);

            //第一轮筛选：筛选出最新创建时间CreateDate的手机号对应的通话数据；
            //组合唯一键：通话日期CallDay+手机号码MobilePhoneNum；
            var linqResult = from t1 in phoneCallCTIPushDatasAll
                             group t1 by new { CallDayGroup = t1.CallDay, MobilePhoneNumGroup = t1.MobilePhoneNum } 
                             into groupTable
                             select new
                             {
                                 //数据创建时间
                                 CreateDate2 = groupTable.Max(x => x.CreateDate),
                                 //通话日期
                                 CallDay2 = groupTable.Key.CallDayGroup,
                                 //手机号码
                                 MobilePhoneNum2 = groupTable.Key.MobilePhoneNumGroup
                             };

            //第二轮筛选：匹配分组后的通话数据对应的id值；
            List<PhoneCallCTIPushData> phoneCallCTIPushDatasPrimary = new List<PhoneCallCTIPushData>();
            Console.WriteLine("打印准备要筛选的：");
            foreach (var item in linqResult)
            {
                PhoneCallCTIPushData phoneCallCTIPushData = phoneCallCTIPushDatasAll
                    .Where(aa => aa.CreateDate == item.CreateDate2 && aa.CallDay == item.CallDay2 && aa.MobilePhoneNum == item.MobilePhoneNum2)
                    .OrderByDescending(bb => bb.Id).FirstOrDefault();
                //将能匹配上的数据插入队列；
                phoneCallCTIPushDatasPrimary.Add(phoneCallCTIPushData);
                Console.WriteLine(item.CreateDate2 + " " + item.MobilePhoneNum2 + " ");
            }
            Console.WriteLine();
            Console.WriteLine("打印结果：");
            foreach (var item in phoneCallCTIPushDatasPrimary)
            {
                Console.WriteLine(item.Id + " " + item.CreateDate + " " + item.MobilePhoneNum);
            }
            Console.ReadKey(); 

 

 

 

 

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