>Hi again Gar,
>
>As far as I recall from VFP Help, UDFs slow down SQL perfomance and work unpredictable. I'm afraid to put this function into long query (which produces ~ 1mln. records)

Scalar funcitons, which this is are not unpredictable. This should give very solid results. Whether it would slow you down -- again, scalar functions don't neccesarily slow down the results. Give this function a try. I guarantee it will do what you need, and the only way to tell whether it will slow performance is to give it a try.
>
>Not sure, that I understand about shared tables. In from clause, of course, I use shared tables. The resulting table isn't shared and it's name is generated unique name.

That is what I mean -- it is an unshared result table. Basically what I am saying is you would not want to use this function as the default value of a key in a table in your shared database -- because the results might not be unique. But in the context of an SQL call the results will be unique and what you are looking for.
>
>Thanks for your help. We'll see, what we can do here.


Hope th is really does help.