TO_DATE function in ORACLE

Question

I was trying the TO_DATE function. Specifically, I noted that the following queries

1. SELECT TO_CHAR(TO_DATE(\'01-01-2015\',\'DD-MM-YYYY\'),\'DD-MO         


        

Answer 1

The default output format of DATE value, resp TO_DATE() function is set by NLS_DATE_FORMAT value. You can verify it with this query:

SELECT * 
FROM V$NLS_PARAMETERS 
WHERE PARAMETER = NLS_DATE_FORMAT';

You can change it on session level for example with

alter session set NLS_DATE_FORMAT = 'DD-MM-YYYY';