Oracle 11g Release 2

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ALTER SESSION SET NLS_DATE_FORMAT = 'YYYY-MM-DD HH24:MI:SS';
CREATE TABLE table_name (address) AS
SELECT 'Rachel Street 27, Floor 42' FROM DUAL UNION ALL
SELECT 'XYZ Street 123456789, Floor 987654321' FROM DUAL;
2 rows affected

SELECT REGEXP_REPLACE(
         address,
         '(\d)(\d)?(\d)?(\d)?(\d)?(\d)?(\d)?(\d)?(\d)?',
         '\9\8\7\6\5\4\3\2\1'
       ) AS reversed
FROM   table_name;


REVERSED


Rachel Street 72, Floor 24

XYZ Street 987654321, Floor 123456789