Question

Have some dates in my local Oracle 11g database that are in this format:

01-JUL-85

How do I change it to this format (mm/dd/yyyy) using PL/SQL:

7/01/1985

With thanks…

Answer 1

If the column is a date datatype then it is only your NLS_DATE settings that are causing them to be displayed in the format DD-MON-YYYY.

To check your current NLS_DATE format run the following:

SELECT value 
  FROM V$NLS_Parameters 
 WHERE parameter ='NLS_DATE_FORMAT';

Oracle stores all dates in an internal binary format and uses the NLS_DATE format to display them (unless explicitly told to display them differently).

You can either alter your NLS_DATE settings to MM/DD/YYYY or TO_CHAR the date column using:

TO_CHAR(<date_column>, 'MM/DD/YYYY')

to see the format you require.

You can alter the NLS_DATE format for your current session or alter the database parameters to change the default NLS_DATE format for the database itself.

If the column is a VARCHAR2 type then you’ll need to convert to a date first and then you can format the output using either of the methods described above.

See: http://ss64.com/ora/syntax-nls.html

and: http://www.dba-oracle.com/t_nls_date_format_sysdate.htm

e.g.

SELECT TO_CHAR(sysdate, 'MM/DD/YYYY') as current_date
  FROM dual;

or

ALTER SESSION SET NLS_DATE_FORMAT = 'MM/DD/YYYY';

SELECT sysdate
 FROM dual;

In pure PL/SQL

DECLARE
   v_date DATE := sysdate;
BEGIN
   DBMS_OUTPUT.put_line(TO_CHAR(v_date, 'MM/DD/YYYY'));
END;