Hello JAMES125,
You may want to try this query instead:
SELECT "Table1" AS Source, t1.*
FROM Table1 t1 LEFT JOIN
Table2 t2 ON t1.Field1 = t2.Field1
WHERE t2.Field1 Is Null
UNION ALL
SELECT "Table2" AS Source, t2.*
FROM Table1 t1 RIGHT JOIN
Table2 t2 ON t1.Field1 = t2.Field1
WHERE t1.Field1 Is Null
Regards,
Patrick