RR FORMAT 과 YY FORMAT 의 차이

Question

제품 : SQL*PLUS
작성날짜 : 2002-04-25
RR FORMAT 과 YY FORMAT 의 차이
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PURPOSE
다음은 RR DATE FORMAT 과 YY DATE FORMAT에 대해서 알아본다.
Explanation
다음의 1) 과 2)의 차이를 잘 살펴 보자 .
1) select to_char(to_date('01-03-27','yy-mm-dd'),'rrrrmmdd')
from dual;
SQL>TO_CHAR(TO_DATE('01-03-27','YY-MM-DD'),'RRRRMMDD')
19010327
2) SQL> select to_char(to_date('01-03-27','rr-mm-dd'),'yyyymmdd')
from dual;
TO_CHAR(TO_DATE('01-03-27','RR-MM-DD'),'YYYYMMDD')
20010327
Reference Documents
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Answer 1

RR was introduced as a Y2K workaround for all those programs that didn't store the century. It has a fixed window - 50 to 99 defaults to twentieth century, 00 to 49 is twenty-first. YY on teh other hand just defaults to the current century. At least in 9.2 it does. I think in earlier version of the database it defaulted to 00 - hence many systems apparently have records that were created in the first century AD.
SQL> SELECT to_char(to_date('01-JAN-50', 'DD-MON-RR'), 'DD-MON-YYYY')
  2  FROM  dual
  3  /
TO_CHAR(TO_
01-JAN-1950
SQL> SELECT to_char(to_date('01-JAN-49', 'DD-MON-RR'), 'DD-MON-YYYY')
  2  FROM  dual
  3  /
TO_CHAR(TO_
01-JAN-2049
SQL> SELECT to_char(to_date('01-JAN-50', 'DD-MON-YY'), 'DD-MON-YYYY')
  2  FROM  dual
  3  /
TO_CHAR(TO_
01-JAN-2050
SQL> SELECT to_char(to_date('01-JAN-49', 'DD-MON-YY'), 'DD-MON-YYYY')
  2  FROM  dual
  3  /
TO_CHAR(TO_
01-JAN-2049
SQL> Cheers, APC