Corrupted redo logs – or just need to restore from a back up with resetlogs – you’ll lose what is in the redologs – but you will have a db… requires a full backupset or level 0 and level 1 incrementals.
Don’t know your dbid – startup mount; select dbid from v$database;
Use controlfile autobackup or show all – hopefully autobackup is on – or you know where the current controlfile backup is.
If you are using an FRA – control file backup maybe in FRA autobackups dir unless explicitly set
rman target / log=dbbackup.log
set dbid=188740450
show controlfile autobackup;
show controlfile autobackup format;
# must be in startup nomount to restore the controlfile
restore controlfile from autobackup;
# must be in mount mode – alter database mount – to restore
restore database;
recover database;
# ok, if you backups and archivelogs are good and you don’t mind losing you redologs…
alter database open resetlogs;