Oh, I see... That simple? Seen like too good to be true. Ill try it and give feedback but i might modify it to split it into two query,...

Vladan, Thank for answering.

I wish it would be that simple. But, like you said, maybe i didn't explain myself well.

UPDATE e

SET Dup = Yes

FROM Employees e

JOIN

(SELECT FirstName, LastName, count(EmployeeID)...