And here's another way (that I am less confident of because it requires that the SUM of attributes for a set is unique), but maybe it'll give you some additional ideas.
SELECT set_id, product, attribute
FROM (
SELECT set_id, product, attribute, m, c
,n=ROW_NUMBER() OVER (PARTITION BY product, m ORDER BY set_id)
FROM (
SELECT set_id, product, attribute
,m=SUM(attribute) OVER (PARTITION BY product, set_id)
,c=COUNT(attribute) OVER (PARTITION BY product, set_id)
FROM #temp) a) a
WHERE n <= c
ORDER BY set_id, attribute;
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