To timestamp function

Question

Am on oracle 10.2.0.3 on solaris:
I have a table that has a field called INSERT_TIME which is a varchar2(50). A row has been inserted using the SYSTIMESTAMP function and stores the timestamp.
select insert_time from table1 ;
Gives me :
26-NOV-07 12.04.57.483120 PM -05:00
I needed to convert this to a timestamp in my SELECT statement(as I will be using this variable to make calculations based on max, min, group by etc)
Hence I tried,
SELECT TO_TIMESTAMP(INSERT_TIME,
'YYYY-MM-DD HH:MI:SS') FROM TABLE1 ;
But I am getting a ORA-01830 error. What format mask can I give to get this right ?
Thanks

Answer 1

Your string contains PM but you are specifying HH24 and PM in your format. The string also contains timezone offset so you need to_timestamp_tz.
SQL> SELECT TO_TIMESTAMP_TZ('26-NOV-07 12.04.57.483120 PM -05:00', 'DD-Mon-RR HH24:MI:SS.FF AM TZH:TZM') tstz FROM dual
ORA-01818: 'HH24' precludes use of meridian indicator
SQL> SELECT TO_TIMESTAMP_TZ('26-NOV-07 12.04.57.483120 PM -05:00', 'DD-Mon-RR HH:MI:SS.FF AM TZH:TZM') tstz FROM dual
TSTZ                                  
26-Nov-07 12:04:57.483120000 PM -05:00
1 row selected.
SQL> SELECT CAST(TO_TIMESTAMP_TZ('26-NOV-07 12.04.57.483120 PM -05:00', 'DD-Mon-RR HH:MI:SS.FF AM TZH:TZM') AS TIMESTAMP) ts FROM dual
TS                          
26-Nov-07 12:04:57.483120 PM
1 row selected.