StackOverflow question #44830265, Sql Server

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CREATE TABLE KrisisShifts_ShiftTrade
  (
     [ValidFrom]      DATETIME2,
     [ValidTo]        DATETIME2,
     [ShiftId]        INT,
     [TradeDate]      DATE,
     [StatusID]       INT,
     [LastActionDate] DATETIME2,
     [OwnerUserID]    INT,
     [WorkerUserID]   INT,
     [WorkerEmail]    VARCHAR(16),
     [Archived]       INT
  );

INSERT INTO KrisisShifts_ShiftTrade
    ([ValidFrom], [ValidTo], [ShiftId], [TradeDate], [StatusID], [LastActionDate], [OwnerUserID],[WorkerUserID],[WorkerEmail], [Archived])
VALUES
    ('2017-06-21 00:26:44', '9999-12-31 23:59:59', 27, '2017-01-27', 3, '2017-01-09 16:23:39.760',45, 34, 'test@hotmail.com', 1),
    ('2017-06-21 00:19:35', '2017-06-21 00:26:44', 27, '2017-01-27', 2, '2017-01-09 16:23:39.760',45, 34, 'test@hotmail.com', 1),
    ('2017-06-21 00:19:16', '2017-06-21 00:19:35', 27, '2017-01-28', 3, '2017-01-09 16:23:39.760',45, 34, 'test@hotmail.com', 1)
;

WITH T1 AS
(
SELECT *, 
       ROW_NUMBER() OVER (PARTITION BY ShiftId, colname ORDER BY ValidFrom)  
       - ROW_NUMBER() OVER (PARTITION BY ShiftId, colname, Colvalue ORDER BY ValidFrom)  AS Grp,
       IIF(DENSE_RANK() OVER (PARTITION BY ShiftId, colname ORDER BY Colvalue) + 
        DENSE_RANK() OVER (PARTITION BY ShiftId, colname ORDER BY Colvalue DESC) = 2, 0,1) AS HasChanges
FROM KrisisShifts_ShiftTrade
       CROSS APPLY ( VALUES 
                    ('TradeDate', CAST(TradeDate AS NVARCHAR(4000))),
                    ('StatusID', CAST(StatusID AS NVARCHAR(4000))),
                    ('LastActionDate', CAST(LastActionDate AS NVARCHAR(4000))),
                    ('OwnerUserID', CAST(OwnerUserID AS NVARCHAR(4000))),
                    ('WorkerUserID', CAST(WorkerUserID AS NVARCHAR(4000))),
                    ('WorkerEmail', CAST(WorkerEmail AS NVARCHAR(4000))),
                    ('Archived', CAST(Archived AS NVARCHAR(4000)))
                   ) CA(Colname, Colvalue)
)
SELECT  ShiftId, colname, Colvalue, MIN(ValidFrom) AS ValidFrom, MAX(ValidTo) AS ValidTo
FROM T1
WHERE HasChanges = 1
GROUP BY ShiftId, colname, Colvalue, Grp
ORDER  BY ShiftId,
          colname,
          ValidFrom;

View schema
Execution time: 0,05 sec, rows selected: 5, rows affected: 3, absolute service time: 0,19 sec