Modify DATE format only for a column

Question

DB table has two or more columns of DATE type of which a column representing "Date of Birth" should not be of the format of TIMESTAMP . When queried it should return "mm/dd/yyyy" format without 'hh:mm:ss' . The others should be as usual.
This is to ensure no changes in the applications querying this columns
Any hints appreciated
Thanks

Answer 1

It depends on NLS_DATE_FORMAT and NLS_TIMESTAMP_FORMAT that is set in the database or session and the datatye used in the table, here is an example:-
U1@BABU>  CREATE TABLE TEST_TAB (DATE1 DATE, DATE2 TIMESTAMP);
Table created.
U1@BABU> INSERT INTO TEST_TAB VALUES (SYSDATE,SYSDATE);
1 row created.
U1@BABU>  COMMIT;
Commit complete.
U1@BABU> SELECT * FROM TEST_TAB;
DATE1 DATE2
22-DEC-06 22-DEC-06 11.44.18.000000 AM
U1@BABU> SELECT * FROM NLS_SESSION_PARAMETERS;
PARAMETER                      VALUE
NLS_LANGUAGE                   AMERICAN
NLS_TERRITORY                  AMERICA
NLS_CURRENCY                   $
NLS_ISO_CURRENCY               AMERICA
NLS_NUMERIC_CHARACTERS         .,
NLS_CALENDAR                   GREGORIAN
NLS_DATE_FORMAT DD-MON-RR
NLS_DATE_LANGUAGE              AMERICAN
NLS_SORT                       BINARY
NLS_TIME_FORMAT                HH.MI.SSXFF AM
NLS_TIMESTAMP_FORMAT DD-MON-RR HH.MI.SSXFF AM
NLS_TIME_TZ_FORMAT             HH.MI.SSXFF AM TZR
NLS_TIMESTAMP_TZ_FORMAT        DD-MON-RR HH.MI.SSXFF AM TZR
NLS_DUAL_CURRENCY              $
NLS_COMP                       BINARY
NLS_LENGTH_SEMANTICS           BYTE
NLS_NCHAR_CONV_EXCP            FALSE
17 rows selected.
U1@BABU> ALTER SESSION SET NLS_DATE_FORMAT='DD-MON-YYYY HH24:MI:SS';
Session altered.
U1@BABU> SELECT * FROM TEST_TAB;
DATE1 DATE2
22-DEC-2006 11:44:18 22-DEC-06 11.44.18.000000 AM
U1@BABU> SELECT TO_CHAR(DATE1,'MON-DD-YYYY HH24:MI:SS') DATE1, TO_CHAR(DATE2,'Month DD YYYY') DATE2
FROM TEST_TAB;
DATE1                DATE2
DEC-22-2006 11:44:18 December  22 2006