Can anyone prove that := works as the documentation says it does?

Hi List, Can anyone here demonstrate a simple sql configuration that proves that the := operator will in fact replace any attribute of the same name, as the documentation says it does? Specfically, I want to see an attribute set in radreply which is then overwritten in radgroupreply, if the user belongs to a certain group. I'm only able to demonstrate that group processing works, but := acts exactly like = for the purposes of this test. Mike-