Format Timestamp with constant precision

I'm trying to format a TIMESTAMP with 6 digits of the fractional part. 'FF' seems to print all available dig开发者_StackOverflow社区its, even if I explicitly declare a TIMESTAMP(6):

DECLARE
  t  TIMESTAMP(6);
BEGIN
  t := SYSTIMESTAMP;
  dbms_output.put_line( TO_CHAR(t, 'FF') );
END;

prints

912387000

Is there a way to get

912387

instead (without using SUBSTRING or something similar)?

Yes that's possible, by using 'FF6':

SQL> DECLARE
  2     t  TIMESTAMP(6);
  3  BEGIN
  4     t := SYSTIMESTAMP;
  5     dbms_output.put_line( TO_CHAR(t, 'FF') );
  6     dbms_output.put_line( TO_CHAR(t, 'FF6') );
  7  END;
  8  /
234771000
234771

PL/SQL procedure successfully completed.

Here is the link to the documentation: http://download.oracle.com/docs/cd/E11882_01/server.112/e17118/sql_elements004.htm#r16c1-t64

Regards, Rob.