Question

I have a table in SQL Server 2005 that I want to aggregate data from, here is an example.

JobName       ProductionCounter       StartDate             EndDate               CounterName        Stage
----------------------------------------------------------------------------------------------------------

200           23                      2012-08-30 13:45:00                          Kilograms          Final
200           2                       2012-08-30 13:45:00                          Bars               Final
    [...]
200           46                      2012-08-30 13:45:00   2012-08-30 17:23:00    Kilograms          Final
200           4                       2012-08-30 13:45:00   2012-08-30 17:23:00    Bars               Final
300           20                      2012-08-30 13:45:00                          Kilograms          1st
300           10                      2012-08-30 18:12:00                          Bars               1st
    [...]
300           40                      2012-08-30 18:12:00   2012-08-30 19:17:00    Kilograms          1st
300           20                      2012-08-30 18:12:00   2012-08-30 19:17:00    Bars               1st

I want to format this into the following

JobName      TotalKilos       TotalBars       StartDate             EndDate               Stage
-----------------------------------------------------------------------------------------------
200          69               6               2012-08-30 13:45:00   2012-08-30 17:23:00   Final
300          60               30              2012-08-30 18:12:00   2012-08-30 19:17:00   1st

This has made me realise I know nothing about SQL. I have tried the following as a start

SELECT JobName, SUM(ProductionCounter)
FROM vwOeeInterval
WHERE (CounterName = 'Kilos')
GROUP BY JobName

SELECT JobName, SUM(ProductionCounter)
FROM vwOeeInterval
WHERE (CounterName = 'Bars')
GROUP BY JobName

My questions are:

1. How do I combine these into one query?

2. How would I query for the columns such as StartDate and Stage? Especially where the EndDate is not filled in until the job completes?

Any pointers would be much appreciated.

Answer 1

Here you go:

SELECT 
JobName, 
SUM(CASE CounterName WHEN 'Kilos' THEN ProductionCounter ELSE 0 END) AS SumKilos,
SUM(CASE CounterName WHEN 'Bars' THEN ProductionCounter ELSE 0 END) AS SumBars,
MIN(StartDate), 
MAX(COALESCE(EndDate, 'undefined date')), 
MAX(Stage)
FROM vwOeeInterval
WHERE CounterName IN ('Kilos', 'Bars')
GROUP BY JobName;

Not sure if this MAX(COALESCE(EndDate, 'undefined date')) works in SQL Server, since datatype’s might clash. You just need COALESCE(), when you want to replace the NULL value. If it does not work, just do MAX(EndDate) and you’re fine.