[AccessD] Checking for "holes" in a sequence using SQL

Hi All,
If I have data similar to:
JOE001
JOE002
JOE003
JOE005
JOE006

Is there a way, using just SQL, to return the next available number in the
sequence, JOE004, and be flexible enough to return JOE007 if JOE004 had
already existed?
Or do I have to use code to iterate through the records to check for
"holes"?

Thanks!
JR




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