How to Find which Files Are Backed Up In RMAN Backup Set 

Query to find the  Backed Up Logs.

SQL> select recid,set_stamp,sequence#,first_change#,next_change# 
     from  v$backup_redolog;

The V$BACKUP_REDOLOG view queries the Control File so this can be done with or 
without a Catalog.

Query to find sequence is kept in which backup piece

SQL> select r.sequence#, p.handle
 from v$backup_piece p, v$backup_redolog r
 where r.set_stamp = p.set_stamp
   and r.set_count = p.set_count
   and r.sequence# = 63 

Query to find datafiles  is kept  in which backup piece. 

 SQL> select d.file#, p.handle
from v$backup_piece p, v$backup_datafile d
where d.set_stamp = p.set_stamp
  and d.set_count = p.set_count
  and d.file# = 3