Yeah, I checked the math after another responder. Either I was smoking
crack at work today (a state likely induced by too much/too little
caffeine) or I mis-noted my numbers.
I'm going to check again when I get back there tomorrow.
But thanks :)
Martin
Dan Nelson wrote:
> In the last episode (Feb 21), Martin said:
>
>>Version: Using 4.1.10 on WinXP pro, currently interacting with it
>>using the Query Browser for testing.
>>
>>I have a table set up that contains a column of DECIMAL(15,12) --
>>financial data, where the precision is highly important. I am
>>building up a series of SQL statements, and I noticed that when doing
>>SUM() on this decimal column, I get a strange rounding error (see
>>below), and was hoping that someone out there can help me with this.
>>
>>My recent test involved the following three values from the column:
>>2.4950
>>2.5950
>>2.7700
>>(Chosen, for this example, as they are precise at few decimal places).
>>
>>When I use a SUM() on these I get: 7.860
>>
>>If I switch the column over to a FLOAT, then the SUM() becomes
>>7.8599998950958
>>
>>Using Excel to test the numbers, or hand-calculating, I get:
>>7.8550.
>
>
> You hand calculations (and Excel) are wrong, apparently. Here's my
> hand-calculation:
>
> 1 11 1
>
> 2.495 5.090
> + 2.595 + 2.770
> ======= =======
> 5.090 7.860
>
> , which matches MySQL's results.
>