Question

I have been trying to introduce a Merge statement into the following SQL query to either update or insert a record into a table Snapshot depending if a match can be found against an existing record based on BuildingId and Timestamp.

Essentially, the query creates a snapshot of records based on an hour time frame, by getting the latest record in the Snapshot table based on BuildingId, and them SUMs all the values that fall within that hour.

-- DECLARE TABLE VARIABLES TO HOLD TEMP DATA
    DECLARE @Output table
    (
      SnapshotId bigint,
      BuildingId bigint,
      [TimeStamp] datetime
    );

-- INSERT ACCUMULATIVE SNAPSHOT DATA INTO BMS_Snapshot TABLE
        ;WITH Snap (BuildingId, Timestamp_Actual, TimestampRange_Start, TimestampRange_End) AS
            (SELECT BMS_Snapshot.BuildingId,  MAX(BMS_Snapshot.Timestamp) AS Timestamp_Actual, 
                dateadd(hh, datediff(hh,0, MAX(BMS_Snapshot.Timestamp)), 0) AS TimestampRange_Start,
                dateadd(mi, +59 , dateadd(hh, datediff(hh,0, MAX(BMS_Snapshot.Timestamp)), 0)) AS TimestampRange_End
                FROM BMS_Snapshot
                GROUP BY BMS_Snapshot.BuildingId)
            INSERT INTO BMS_Snapshot 
                (BuildingId, Timestamp, Emissions, EnergyUse, NABERS, Lighting, Heating,
                    Cooling, InternalEquipment, Fans, WaterSystems, NotClassified, Electricity,
                    Gas, Water, Other, [Range])
            OUTPUT inserted.SnapshotId, inserted.BuildingId, inserted.TimeStamp INTO @Output
            SELECT  [Snapshot].BuildingId,
                MAX(TimestampRange_End) AS Timestamp,
                SUM([Snapshot].Emissions) AS Emissions,
                SUM([Snapshot].EnergyUse) AS EnergyUse,
                AVG([Snapshot].NABERS) AS NABERS,
                SUM([Snapshot].Lighting) AS Lighting,
                SUM([Snapshot].Heating) AS Heating,
                SUM([Snapshot].Cooling) AS Cooling,
                SUM([Snapshot].InternalEquipment) AS InternalEquipment,
                SUM([Snapshot].Fans) AS Fans,
                SUM([Snapshot].WaterSystems) AS WaterSystems,
                SUM([Snapshot].NotClassified) AS NotClassified,
                SUM([Snapshot].Electricity) AS Electricity,
                SUM([Snapshot].Gas) AS Gas,
                SUM([Snapshot].Water) AS Water,
                SUM([Snapshot].Other) AS Other,
                1 AS [Range]
            FROM
                Snap INNER JOIN 
                BMS_Snapshot AS [Snapshot] ON Snap.BuildingId = [Snapshot].BuildingId
            WHERE 
                /* RANGE - FILTER ONLY 10 MINUTE SNAPSHOTS */
                [Snapshot].[Range] = 0 AND
                [Snapshot].[TimeStamp]
                BETWEEN TimestampRange_Start AND TimestampRange_End
            GROUP BY [Snapshot].BuildingId

I’ve tried putting together the merge statement, but can seem to be able to get the update to work with a ‘Select From…’

Thanks.

EDIT:

After some playing around, I now have the following query, which does update the correct record if it exists, but does not insert if it does not exist:

    -- INSERT ACCUMULATIVE SNAPSHOT DATA INTO BMS_Snapshot TABLE
    ;WITH Snap (BuildingId, Timestamp_Actual, TimestampRange_Start, TimestampRange_End) AS
        (SELECT BMS_Snapshot.BuildingId,  MAX(BMS_Snapshot.Timestamp) AS Timestamp_Actual, 
            dateadd(hh, datediff(hh,0, MAX(BMS_Snapshot.Timestamp)), 0) AS TimestampRange_Start,
            dateadd(mi, +59 , dateadd(hh, datediff(hh,0, MAX(BMS_Snapshot.Timestamp)), 0)) AS TimestampRange_End
            FROM BMS_Snapshot
            GROUP BY BMS_Snapshot.BuildingId)
        MERGE INTO BMS_Snapshot AS t
            USING
                (SELECT [Snapshot].BuildingId,
                    MAX(TimestampRange_End) AS Timestamp,
                    SUM([Snapshot].Emissions) AS Emissions,
                    SUM([Snapshot].EnergyUse) AS EnergyUse,
                    AVG([Snapshot].NABERS) AS NABERS,
                    SUM([Snapshot].Lighting) AS Lighting,
                    SUM([Snapshot].Heating) AS Heating,
                    SUM([Snapshot].Cooling) AS Cooling,
                    SUM([Snapshot].InternalEquipment) AS InternalEquipment,
                    SUM([Snapshot].Fans) AS Fans,
                    SUM([Snapshot].WaterSystems) AS WaterSystems,
                    SUM([Snapshot].NotClassified) AS NotClassified,
                    SUM([Snapshot].Electricity) AS Electricity,
                    SUM([Snapshot].Gas) AS Gas,
                    SUM([Snapshot].Water) AS Water,
                    SUM([Snapshot].Other) AS Other,
                    1 AS [Range]
                FROM
                    Snap INNER JOIN 
                    BMS_Snapshot AS [Snapshot] ON Snap.BuildingId = [Snapshot].BuildingId
                WHERE 
                    /* RANGE - FILTER ONLY 10 MINUTE SNAPSHOTS */
                    [Snapshot].[Range] = 0 AND
                    [Snapshot].[TimeStamp]
                    BETWEEN TimestampRange_Start AND TimestampRange_End
                GROUP BY [Snapshot].BuildingId) As s
            ON t.BuildingId = s.BuildingId
            WHEN MATCHED AND (t.Timestamp = s.Timestamp AND
                t.[Range] = 1) THEN
                    UPDATE SET
                        t.Emissions = s.Emissions,
                        t.EnergyUse = s.EnergyUse,
                        t.NABERS = s.NABERS,
                        t.Lighting = s.Lighting,
                        t.Heating = s.Heating,
                        t.Cooling = s.Cooling,
                        t.InternalEquipment = s.InternalEquipment,
                        t.Fans = s.Fans,
                        t.WaterSystems = s.WaterSystems,
                        t.NotClassified = s.NotClassified,
                        t.Electricity = s.Electricity,
                        t.Gas = s.Gas,
                        t.Water = s.Water,
                        t.Other = s.Other
                WHEN NOT MATCHED BY t THEN
                    INSERT 
                        (BuildingId, Timestamp, EnergyUse, NABERS, Lighting, Heating,
                        Cooling, InternalEquipment, Fans, WaterSystems, NotClassified,
                        Electricity, Gas, Water, Other, [Range])
                    VALUES
                        (s.BuildingId, s.Timestamp, s.EnergyUse, s.NABERS, s.Lighting, s.Heating,
                        s.Cooling, s.InternalEquipment, s.Fans, s.WaterSystems, s.NotClassified,
                        s.Electricity, s.Gas, s.Water, s.Other, 1);

Answer 1

MERGE BMS_Snapshot target USING (SELECT BMS_Snapshot.BuildingID, ...) 
 source(BuildingID,...)
  ON target.BuildingID = source.BuildingID 
  AND target.Timestamp = source.Timestamp 
WHEN MATCHED THEN 
    UPDATE SET Emissions = source.Emissions, ... 
WHEN NOT MATCHED BY target THEN 
    INSERT (BuildingID, ...) 
    VALUES (source.BuildingID, ...);

I apologize for the format, as I’m on a tablet at the moment.

per your update, you are only looking at buildingid in the ON clause, but you also need your timestamp. The buildingid matches but the filter on the WHEN MATCHED eliminates it from the update.