使用to_char函数在sql中转换日期

Question

I would like to convert the following date to this format(DD-MON-YYYY).

I tried executing the below query but I got the error saying "date format not recognised".

select to_char(to_date('Sat Dec 01 00:00:00 IST 2012','EEE Mon dd HH:mm:ss z yyyy'),'DD-MON-YYYY') from dual;

Answer 1

For everything but the time zone:

'DY MON DD HH24:MI:SS YYYY'

For timezone support you need to use a conversion function that supports a timezone like TO_TIMESTAMP_TZ() and have the time zone name as one Oracle recognizes in the form it recognizes.

select to_char( TO_TIMESTAMP_TZ( 
        REPLACE( 'Sat Dec 01 21:00:00 IST 2012','IST','Asia/Calcutta'),
       'DY MON DD HH24:MI:SS TZR YYYY'),'DD-MON-YYYY') from dual;

The relation between time zone names and abbreviations is one to many for most.

SELECT tzname, tzabbrev FROM v$timezone_names where TZABBREV = 'IST'

For your example it would probably be easier to remove some or all of the date parts you don't need in the output before conversion.

select to_char( to_date( replace('Sat Dec 01 21:00:00 IST 2012','IST',''),
       'DY MON DD HH24:MI:SS YYYY'),'DD-MON-YYYY') from dual;