Question

I need to extract data from the tables RawData and RawDataMeter and sum the ‘Value’ field for each unique MeterId for the last 10 minutes (relative to the TimeStamp). The RawData and RawDataMeter tables as joined via the RawDataId field using a INNER JOIN, records are only selected when the RawData.BuildingId and RawDataMeter.MeterId exist within the BuildingMeter table. I.e. the query needs select the fields from RawData and RawDataMeter tables only if they exist in the BuildingMeter table, it then needs to get the latest record for each meter (based on the TimeStamp) and then retrieve the last 10 minutes worth of values for that meter. Once it has these values, it needs to SUM each meters 10 minutes worth of values and output the results.

The query I have so far is:

SELECT TOP (SELECT COUNT(DISTINCT BuildingMeterId) FROM BuildingMeter)
    MeterId, BuildingId, TimeStamp, Value
FROM
    RawData
    INNER JOIN 
        RawDataMeter 
    ON RawData.RawDataId = RawDataMeter.RawDataId
WHERE
    EXISTS
        (SELECT 
            BuildingId,
            BuildingMeterId
        FROM
            BuildingMeter)
ORDER BY
    TimeStamp DESC

Which produces the following results:

1   1   2012-05-16 12:51:00.000 216
2   1   2012-05-16 12:51:00.000 876989
3   1   2012-05-16 12:51:00.000 389164
4   1   2012-05-16 12:51:00.000 1.298896E+07
5   1   2012-05-16 12:51:00.000 283378
6   1   2012-05-16 12:51:00.000 1541438
7   1   2012-05-16 12:51:00.000 4241823
8   1   2012-05-16 12:51:00.000 5761659
9   1   2012-05-16 12:51:00.000 3
10  1   2012-05-16 12:51:00.000 0
11  1   2012-05-16 12:51:00.000 23
12  1   2012-05-16 12:51:00.000 3822836
13  1   2012-05-16 12:51:00.000 4983960
14  1   2012-05-16 12:51:00.000 909497
15  1   2012-05-16 12:51:00.000 7724438

BuildingMeter table sample (i’ve only included 1 building with 15 meters (this is variable)):

BuildingId  BuildingMeterId
1   1
1   2
1   3
1   4
1   5
1   6
1   7
1   8
1   9
1   10
1   11
1   12
1   13
1   14
1   15

The sample data for the last 30 records from RawData:

RawDataId, TimeStamp, BuildingId
21677   2012-05-16 00:03:00.000 1
21678   2012-05-16 00:03:00.000 1
21679   2012-05-16 00:03:00.000 1
21680   2012-05-16 00:03:00.000 1
21681   2012-05-16 00:03:00.000 1
21682   2012-05-16 00:03:00.000 1
21683   2012-05-16 00:03:00.000 1
21684   2012-05-16 00:03:00.000 1
21685   2012-05-16 00:03:00.000 1
21686   2012-05-16 00:03:00.000 1
21687   2012-05-16 00:03:00.000 1
21688   2012-05-16 00:03:00.000 1
21689   2012-05-16 00:03:00.000 1
21690   2012-05-16 00:03:00.000 1
21691   2012-05-16 00:03:00.000 1
21662   2012-05-16 00:02:00.000 1
21663   2012-05-16 00:02:00.000 1
21664   2012-05-16 00:02:00.000 1
21665   2012-05-16 00:02:00.000 1
21666   2012-05-16 00:02:00.000 1
21667   2012-05-16 00:02:00.000 1
21668   2012-05-16 00:02:00.000 1
21669   2012-05-16 00:02:00.000 1
21670   2012-05-16 00:02:00.000 1
21671   2012-05-16 00:02:00.000 1
21672   2012-05-16 00:02:00.000 1
21673   2012-05-16 00:02:00.000 1
21674   2012-05-16 00:02:00.000 1
21675   2012-05-16 00:02:00.000 1
21676   2012-05-16 00:02:00.000 1

Sample for RawDataMeter:

MeterId, RawDataId, Value
15  21691   7722613
14  21690   908944
13  21689   4982947
12  21688   3821899
11  21687   6
10  21686   0
9   21685   0
8   21684   5761656
7   21683   4240048
6   21682   1541372
5   21681   283223
4   21680   1.298603E+07
3   21679   388137
2   21678   876121
1   21677   0
15  21676   7722615
14  21675   908944
13  21674   4982947
12  21673   3821899
11  21672   5
10  21671   0
9   21670   0
8   21669   5761656
7   21668   4240052
6   21667   1541372
5   21666   283223
4   21665   1.298604E+07
3   21664   388137
2   21663   876122
1   21662   0

EDIT:

Following the steps outlined by Gordon, I managed to get the following SQL query, which appears to be working correctly:

WITH 
    RawMeterData (MeterId, BuildingId, TimeStamp, LatestTimeStamp, Value) AS
(SELECT
    RawDataMeter.MeterId, 
    RawData.BuildingId, 
    RawData.TimeStamp, 
    MAX(RawData.TimeStamp) OVER (PARTITION BY BuildingMeter.BuildingMeterId) AS LatestTimeStamp, 
    RawDataMeter.Value
FROM
    BMS_RawData AS RawData
    INNER JOIN 
        BMS_RawDataMeter AS RawDataMeter 
    ON RawData.RawDataId = RawDataMeter.RawDataId
    INNER JOIN
        (SELECT 
            DISTINCT BuildingId,
            BuildingMeterId
        FROM
            AST_BuildingMeter) as BuildingMeter 
        ON RawData.BuildingId = BuildingMeter.BuildingId AND 
        RawDataMeter.MeterId = BuildingMeter.BuildingMeterId)
SELECT MeterId, BuildingId, SUM(Value) AS Value FROM RawMeterData WHERE RawMeterData.TimeStamp 
BETWEEN DATEADD(mi, -9, LatestTimeStamp) AND LatestTimeStamp
GROUP BY MeterId, BuildingId

Answer 1

I don’t have enough time to write the query.

You need to do the following:

1. Change the exists clause to be a join, on the two fields. You should add a “distinct” to the inner select to prevent duplicates from affecting you.
2. Use the windows function “max(timestamp) over (partition by buildingmeterid)” to get the most recent time stamp.
3. Make this a subquery (or use a “with” clause).
4. Select the records based on the difference between the max timestamp and the timestamp
5. Aggregate the results to get the sum.

For writing the query, it would help if you put aliases in front of all the field names. The casual reader cannot tell which fields are from which tables.