Find the date and patch number applied in Oracle Database.

List the patches applied in Oracle Database

Go to directory
CD %ORACLE_HOME%\OPatch
opatch lspatches

List the patches with lsinventory

-- on Windows system:
CD %ORACLE_HOME%\OPatch
opatch lsinventory

--On Linux
$ORACLE_HOME/OPatch/opatch lsinventory|grep "Patch description"

Check the patches more in details with lsinventory details command

--on Windows:
%ORACLE_HOME%\opatch\opatch lsinventory -details

--on linux
$ORACLE_HOME/OPatch/opatch lsinventory -details

Check Patches from SQLPLUS by connecting with SYSDBA

-- For upto 11g
COLUMN action_time FORMAT A20
COLUMN action FORMAT A20

COLUMN version FORMAT A10
COLUMN comments FORMAT A30
COLUMN bundle_series FORMAT A10

SELECT TO_CHAR(action_time, 'DD-MON-YYYY HH24:MI:SS') AS action_time,
action,
 version, id, comments, bundle_series
FROM   sys.registry$history
ORDER by action_time;

--From 12c onwards
col action_time for a28
col action for a8
col version for a8
col comments for a30
col status for a10
set line 999 pages 999
select patch_id,  version, status, Action,Action_time from dba_registry_sqlpatch order by action_time;

Check patch is applied or not with DBMS package

--- Put patch number which you want to check
select xmltransform(dbms_qopatch.is_patch_installed('29494060'),dbms_qopatch.get_opatch_xslt) "Patch installed?" from dual;

Check all patches applied from DBMS

 set serverout on;
 exec dbms_qopatch.get_sqlpatch_status;