GL_Cancelled_Date displaying incorrect year

Question

I currently have around 560 rows of bad data where GL_Encumbered_Date and TO_CHAR(PRD.GL_ENCUMBERED_DATE,'YYYY'  display correctly. The problem lies in PRD.GL_CANCELLED_DATE which displays correctly (example: 30-APR-10) but TO_CHAR(PRD.GL_CANCELLED_DATE, 'DD-MON-YYYY') for the same row displays as 30-APR-0010.
I have separated out the incorrect year with: to_char(prd.gl_cancelled_date,'YYYY') where each of the 560 rows display 0010 instead of 2010.
I am unsure if arithmetic with dates is allowed within SQL- but am curious if the operation date + number will result in a date. If this is so, how could one go about taking 0010 as a date and add 2000 to create 2010 for: PRD.GL_CANCELLED_DATE.

Answer 1

i don't understand .. what is the problem :
SQL> alter session set nls_date_format = 'dd-mon-yy';
Session altered.
SQL> select TO_date('30-APR-10', 'DD-MON-YY') from dual;
TO_DATE('
30-apr-10
SQL> alter session set nls_date_format = 'dd-mon-yyyy';
Session altered.
SQL> select TO_date('30-APR-10', 'DD-MON-YY') from dual;
TO_DATE('30
30-apr-2010
SQL>