SELECT non NULL records, then sort them

[VBAhack]

Having trouble sorting records (using ADO with Excel VBA on Access DB file). The field I'm interested in can have numeric or NULL values. I only want the records with non-NULL values for field XX and then sort them. Using the following select statement, I get the records I want, but they aren't sorted. How to fix?

SELECT * FROM TestTable WHERE NOT ISNULL(XX) ORDER BY XX