> 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.
0.1 cannot be represented exactly using floating point numbers (the same way as 1/3 cannot be represented exactly using decimal numbers). You're bound to suffer from round-off errors. Use numeric for exact, decimal math. Bye, Chris. -- Chris Mair http://www.1006.org ---------------------------(end of broadcast)--------------------------- TIP 9: In versions below 8.0, the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match
