Ok. Take the following query:

select txamount from laytransactions where layid = 5

The result is:

-7.34
7.34
-29.36
-8.09
37.49
-0.04

Now, I run the following query:

select sum(txamount) from laytransactions where layid = 5

The result is:

-8.53483950180589E-16

What the heck? Why isn't it zero???

I am using FB 1.0. The txamount column is a double precision. But,
shouldn't summing a bunch of numbers with exactly 2 decimal places yield a
result with two digits, and not some random very small number???

-Joe