help with an sql statement please

Hi All

I need to get the maximum Decision number from my decision table where Enquiry Number = 1 but im not having much luck, can anyone help please (Niether are auto number field or primary key)

thanks

Gibbo

e.g. Select Maximum Decision_No from Decisions Where Enquiry_No = 1

Code Snippet

SELECT max( Decision_No )
FROM Decisions
WHERE Enquiry_No = 1