How to find patches applied/installed on Oracle database

SELECT
e.patch_name,
c.end_date,
a.bug_number,
b.applied_flag
FROM
ad_bugs a,
ad_patch_run_bugs b,
ad_patch_runs c,
ad_patch_drivers d ,
ad_applied_patches e
WHERE
AND a.bug_id = b.bug_id
AND b.patch_run_id = c.patch_run_id
AND c.patch_driver_id = d.patch_driver_id

AND d.applied_patch_id = e.applied_patch_id

For Oracle 11g Release:

1. using Opatch utility

cd $ORACLE_HOME/OPatch

opatch lsinventory

2.  select * from sys.registry$history;



For Oracle 12c Release:

1. Opatch utility

cd $ORACLE_HOME/OPatch

opatch lsinventory

2. using dba_registry_sqlpatch view:

SQL> select * from dba_registry_sqlpatch;

3. using package dbms_qopatch

SQL> set serverout on

SQL> exec dbms_qopatch.get_sqlpatch_status;