Sum a column then group based on another column that has duplicate values

Question

SELECT
    ShipDate, Stockroom, COLineNumber, CONumber, ShippedQty, ReversedQty, 
    CASE WHEN ReversedQty IS NULL THEN ShippedQty ELSE ReversedQty * - 1 END AS FinalShippedQty
FROM MyTable  
WHERE CONumber = 'RAN-00001000'  

This is my current output based on the query above:

ShipDate  Stockroom CoLineNumber CONumber     ShippedQty ReversedQty FinalShippedQty
--------  --------- ------------ ------------ ---------- ----------- ---------------
8/7/2013  01        1            RAN-00001000 10         *NULL*      10
8/7/2013  41        2            RAN-00001000 12         *NULL*      12
8/7/2013  41        3            RAN-00001000 24         *NULL*      24
8/7/2013  41        4            RAN-00001000 12         *NULL*      12
8/7/2013  41        4            RAN-00001000 *NULL*     2           -2
8/7/2013  01        5            RAN-00001000 50         *NULL*      50
8/7/2013  41        6            RAN-00001000 12         *NULL*      12
8/7/2013  41        6            RAN-00001000 *NULL*     3           -3
8/7/2013  41        6            RAN-00001000 *NULL*     3           -3

As you notice above that CoLineNumber 4 is twice because we had an original entry then reversed the Qty by 2 and then CoLineNumber 6 has three entries for the same cause. I would like to Summarize the FinalShippedQty Column for those rows that have the same CoLineNumber and belong to the same CONumber. This is only one order here but usually the true extract could quite a few.

Here is the output I would like to see:

ShipDate  Stockroom CoLineNumber CONumber     FinalShippedQty
--------  --------- ------------ ------------ ---------------
8/7/2013  01        1            RAN-00001000 10
8/7/2013  41        2            RAN-00001000 12
8/7/2013  41        3            RAN-00001000 24
8/7/2013  41        4            RAN-00001000 10
8/7/2013  01        5            RAN-00001000 50
8/7/2013  41        6            RAN-00001000 6

Please let me know if you have any questions or need further explanation. again keep in mind that the table I have has hundreds of CoNumbers but I just want to Sum up the FinalShippedQty for those CoLineNumbers that are equal and belong to that specific CONumber.

EDIT: I've added the Stockroom column which I didn't have the first time.

Answer 1

I believe you just need to introduce grouping to your query:

SELECT
    ShipDate, Stockroom, COLineNumber, CONumber, ShippedQty, ReversedQty,
    SUM(CASE WHEN ReversedQty IS NULL THEN ShippedQty ELSE ReversedQty * - 1 END) AS FinalShippedQty
FROM MyTable  
WHERE CONumber = 'RAN-00001000'
GROUP BY
    ShipDate, Stockroom, COLineNumber, CONumber
;

Note also that your CASE expression could be rewritten using COALESCE:

SELECT
    ShipDate, Stockroom, COLineNumber, CONumber,
    SUM(COALESCE(-ReversedQty, ShippedQty)) AS FinalShippedQty
FROM MyTable  
WHERE CONumber = 'RAN-00001000'
GROUP BY
    ShipDate, Stockroom, COLineNumber, CONumber
;