Re: strange sum behaviour

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

[expected to be 0]

Floating-point numbers are typically inaccurate like that, and if you
rely in equality comparisons, you're doing something wrong.  You should
use numeric or fix your application to take these errors into account.

--
Peter Eisentraut
http://developer.postgresql.org/~petere/