prova=> select * from a;
int_2| int_4| int_8
-----+----------+-------------------
32767|2147483647|9223372036620802086
32767|2147483647|9223372036620802086
(2 rows)
prova=> select avg(int_2), avg(int_4), avg(int_8) from a;
avg|avg| avg
---+---+----------
-1| -1|-233973722
(1 row)
Jose'