CI or MySQL bug?

[eluser]Einspruch[/eluser]
This code in my model works:

Code:

SUM(Billing.gross_amt) AS gross_revenue

but when I try to round the result to just two decimals using

Code:

ROUND(SUM(Billing.gross_amt),2) AS gross_revenue

I get this error:

Unknown column '2' in 'field list'

Any ideas as to what I am doing incorrectly? Is this a MySQL syntax issue or a CI issue?

Thanks!

Robert