SQL> select to_char(sysdate, 'MM') from dual;

TO
--
11

SQL> select extract(year from sysdate) as year
  2  ,      extract(month from sysdate) as month
  3  from   dual;

      YEAR      MONTH
---------- ----------
      2006         11

We have a column which is of Varchar Datatype and having values like 'JUN-02, JUL-01, AUG-99....'
I would like the output to be:
Year: 2002, 2001, 1999
Month: 6,7,8 (numbers)

select to_char(to_date('JUN-02','MON-RR'),'MM  YYYY') from dual;
select to_char(to_date('JUL-01','MON-RR'),'MM  YYYY') from dual;
select to_char(to_date('AUG-99','MON-RR'),'MM  YYYY') from dual;

     
UPDATE tablename
SET YEAR= to_char(TO_DATE('Column1','MON-RR'),'YYYY')
  

SQL> create table test (column1 varchar2(10), col_date varchar2(4));

Table created.

SQL> insert into test (column1) values ('lip-06');

1 row created.

SQL> insert into test (column1) values ('kol-99');

1 row created.

SQL> update test set
  2    col_date = to_char(to_date(column1, 'mon-yy'), 'yyyy');

2 rows updated.

SQL> select * From test;

COLUMN1    COL_
---------- ----
lip-06     2006
kol-99     2099

SQL>

Column1
JUN-06
JUL-05
FEB-99
AUG-06
SEP-05

update Tablename set
    YEAR = to_char(to_date('Column1', 'mon-yy'), 'yyyy')

update Tablename set
    YEAR = to_char(to_date('Column1', 'mon-yy'), 'yyyy')