How to find the version of a file?

SELECT a.app_short_name, a.subdir, a.filename, b.version
FROM   apps.ad_files a,
       apps.ad_file_versions b
WHERE  a.FILENAME like '%ibyxmlv%'
AND    a.file_id = b.file_id
AND    a.app_short_name = 'IBY' --- e.g. : ASF, AMS....
AND    b.creation_date = (SELECT MAX (creation_date)
                          FROM apps.ad_file_versions ver
                          WHERE ver.file_id = a.file_id)