Hi list

I have following select statement:

r.odbiorca_id
cast(r.data_wyj - r.data_wej as integer) as o_sklad
count (r.kod_8)
sum(r.waga)
from mgp_role r

for correct syntax I have to add group by part, but how I can put computed
column there.
One can say - create a view or add computed column to the table. Is there
another solution?

TIA
Marcin