I'm just guessing here, but you might need the APPLY operator.
Something like this:
SELECT tt.Name, tt.installed
FROM @PatchGroup pg
CROSS APPLY dbo.fn_PatchInfo ('Desktop', pg.patchgroup) pi
Luis C.
General Disclaimer:
Are you seriously taking the advice and code from someone from the internet without testing it? Do you at least understand it? Or can it easily kill your server?
How to post data/code on a forum to get the best help: Option 1 / Option 2