Not sure but considering your latest requirements, I think a slight modification to Lowell's original suggestion might perform better:
With MyCTE (Product,Parts,Status)
AS
(
SELECT 'Laptop1','mouse','OK' UNION ALL
SELECT 'Laptop1','screen','OK' UNION ALL
SELECT 'Laptop1','button','PASS' UNION ALL
SELECT 'Laptop2','mouse','OK' UNION ALL
SELECT 'Laptop2','screen','OK' UNION ALL
SELECT 'Laptop2','button','NOT OK' UNION ALL
SELECT 'Laptop3','button','OK' UNION ALL
SELECT 'Laptop3','screen','PASS' UNION ALL
SELECT 'Laptop3','mouse','PASS' UNION ALL
SELECT 'Laptop4','button','PASS' UNION ALL
SELECT 'Laptop4','screen','PASS' UNION ALL
SELECT 'Laptop4','mouse','PASS' )
select Product
, status=CASE MIN(status)
WHEN 'OK' THEN MIN(status)
WHEN 'PASS' THEN 'OK'
ELSE 'NOT OK' END
FROM MyCTE
GROUP BY Product
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