SQL>
SQL> SELECT TO_TIMESTAMP_TZ('2005-05-13 07:15:31.1234 PST',
2 'YYYY-MM-DD HH24:MI:SS.FF TZR')
3 FROM dual;
TO_TIMESTAMP_TZ('2005-05-1307:15:31.1234PST','YYYY-MM-DDHH24:MI:SS.FFTZR')
---------------------------------------------------------------------------
13-MAY-05 07.15.31.123400000 AM PST
SQL>