I don't think you can do it all in one query. But if you had a small vba routine along these lines
Sub YourRoutine()
Dim SqlUpdate as String 'you have to create the sql for Update
Dim SqlInsert as String 'you have to create the sql for Insert
Dim SQL as string
Dim db as dao.database
set db = currentdb
If DCount("ID","YourTable", criteria you are using) >0 Then
'update code here
db.execute sqlUpdate , dbfailonerror
else
'Insert code here
db.execute sqlInsert , dbfailonerror
end if
see
http://www.techonthenet.com/access/f...ain/dcount.php
for DCount
oops I see theSshabz responded while I was typing.