How to use sequence in FUNCTION?

[Dmitry Bond.]

Hi.

Please help me. I need to port one stored function from Oracle to DB2.
In Oracle there is a sequence used, like this:

SELECT seqTF.nextval INTO seq_nextval FROM dual;

I have lost 2 hours trying to find how to do the same thing in DB2. :-
( Unfortuinately without success.

I tried following variants:

VALUES NEXT VALUE FOR seqTF INTO seq_nextval;
seq_nextval := NEXT VALUE FOR seqTF;
seq_nextval := (SELECT NEXT VALUE FOR seqTF FROM SYSIBM.SYSDUMMY1);

Unfortuinately all variants listed above do not work.

Could you please help me with it?

I need it for DB2 8.2.7.
Function should be as fast as possible, not use any additional tables.

Regards,
Dmitry.

PS. Here is the full code of function I converted from Oracle:

CREATE FUNCTION GetSysTimeFraction() RETURNS timestamp
LANGUAGE SQL
NOT DETERMINISTIC
BEGIN ATOMIC
DECLARE time_str VARCHAR(50);
DECLARE fraction_str VARCHAR(50);
DECLARE seq_nextval INTEGER;
DECLARE tTmStmp TIMESTAMP;

seq_nextval := NEXT VALUE FOR seqTF;

tTmStmp := current timestamp;
time_str := cast(tTmStmp as char(26));
fraction_str := '000000' || cast(cast(substr(time_str, 21, 3) as int)
* 100 + seq_nextval as char(9));
fraction_str := substr(fraction_str, length(fraction_str) - 6, 6);
time_str := substr(time_str, 1, 20);
RETURN cast((time_str || fraction_str) as timestamp);
END@