Perhaps this works for you?
WITH JoinedTables AS (
SELECT a.OriginCode, a.OCID, b.DestID, b.Ordered
FROM LOC a
JOIN DEST b ON a.OCID = b.OCID)
SELECT OriginCode, DestID, Total=SUM(Ordered)
FROM (
SELECT OriginCode=STUFF((
SELECT ',' + OriginCode
FROM JoinedTables b
WHERE a.DestID = b.DestID
ORDER BY OriginCode
FOR XML PATH('')), 1, 1, '')
,DestID, Ordered
FROM JoinedTables a) a
GROUP BY OriginCode, DestID;
My thought question: Have you ever been told that your query runs too fast?
My advice:
INDEXing a poor-performing query is like putting sugar on cat food. Yeah, it probably tastes better but are you sure you want to eat it?
The path of least resistance can be a slippery slope. Take care that fixing your fixes of fixes doesn't snowball and end up costing you more than fixing the root cause would have in the first place.
Need to UNPIVOT? Why not CROSS APPLY VALUES instead?[/url]
Since random numbers are too important to be left to chance, let's generate some![/url]
Learn to understand recursive CTEs by example.[/url]
[url url=http://www.sqlservercentral.com/articles/St