SUM() and GROUP BY

Does this seem right?

druid=> SELECT COUNT(*) FROM acctrans;
count
-----
0
(1 row)

druid=> SELECT client_id, SUM(tramount) FROM acctrans GROUP BY client_id;
client_id|sum
---------+---
|
(1 row)

If there are no rows in the table then shouldn't the result be no rows
when GROUP BY is used? Further, What about this?

druid=> SELECT SUM(tramount) FROM acctrans;
sum
---

(1 row)

Shouldn't that be 0.00?

What will the NUMERIC or DECIMAL types do in these situations? It
looks like INTEGER has the same behaviour as MONEY (which tramount is.)

--
D'Arcy J.M. Cain <darcy(at){druid|vex}.net> | Democracy is three wolves
http://www.druid.net/darcy/ | and a sheep voting on
+1 416 424 2871 (DoD#0082) (eNTP) | what's for dinner.