How to find whether CPU patch is applied to RDBMS Oracle Home

Problem:

I want to find out what all CPU patches/Patch set updates have been applied to my RDBMS Oracle Home.

Answer:

Use the below SQL command to see all the PSUs/CPUs applied to your database.

select * from dba_registry_history ;

Alternately, we can check successful CPU patch installation logs under $ORACLE_HOME/cfgtoollogs/catbundle directory.