strange sum behaviour

["Andrew Baerg" <andrew.baerg@xxxxxxxxx>]

Hi,

I am getting strange results from the sum function as follows:

corp=# select amount from acc_trans where trans_id=19721 and chart_id=10019;
amount
---------
   4.88
  117.1
-121.98
(3 rows)

corp=# select sum(amount) from acc_trans where trans_id=19721 and
chart_id=10019;
        sum
----------------------
-1.4210854715202e-14
(1 row)


amount is defined as double precision. I noticed that if I cast amount
as numeric, the sum comes out 0 as expected.

I am using postgresql 8.0.1

Thanks in advance for any help or suggestions.

Andrew Baerg