In the 1.00 release docs, it is stated that
'a side effect of the changes enabling the grouping by UDF is that,
whereas previously you could not call built-in firebird functions in
GROUP BY, now you can by creating a dummy UDF wrapper.

As the editor also requests in it's document "it would be good to get
some examples here, please', in other words, could someone elaborate :)

The example given suggest that I could to a group by a the result of the
subselect, how could this be done ?

thank in advance
Didier