NZ function not recognised

[elliotgr]

I am running Access 2007 opening a 2003 database. The Nz function is not working in a normal select query. In fact Access does not recognise it as it stays in lower case. Am I missing a reference or is there some other setting?

 

[elliotgr]

Answered my own question. It can only be used if the other grouped fields are also not null.
I was doing a count of the date and trying to show the date, but when the date is null, Nz appears not to work.