Hi All.
Sorry to post this argument another time, but...

Now i got the decimal parts of the resulting hour in centesimal:
eg:

3,30 is turn into 3,50

This is the code thanks to Ann:

sum( ( cast(presenze.orelavorate - cast( '0.00.00' as time ) as
numeric(9,3) ) )/60/60 )

give me 3,50.
but I want 3,30. As usual

How to tell to interbase to transform a centesimal time in
sessagesimal one?

TIA
Arnaldo