SELECT TO_CHAR (CURRENT_TIMESTAMP AT TIME ZONE 'GMT',
                'YYYY-MM-DD HH24:MI:SS TZD')
          AS curr_timestamp,
       COUNT (db_user) AS failed_count
  FROM sys.dba_common_audit_trail
 WHERE     action BETWEEN 100 AND 102
       AND returncode != 0
       AND extended_timestamp >=
              CURRENT_TIMESTAMP - TO_DSINTERVAL ('0 0:30:00');