Обсуждение: BUG #14184: Function is running correct but not showing output

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On Mon, Jun 13, 2016 at 8:40 AM,  <zzia88@gmail.com> wrote:

> -----<<<<<<My function Coding>>>>----
> CREATE OR REPLACE FUNCTION FACTORIAL(IN NUM BIGINT,OUT FACT BIGINT) AS $$
> DECLARE
>         FACT BIGINT;
>  BEGIN
>         FOR I IN REVERSE 1..NUM LOOP
>                 FACT:=FACT*I;
>         END LOOP;
> END;
> $$ LANGUAGE plpgsql;
> -----<<<<<<<<<<<<>>>>>>>>>>>>>-----
> SELECT* FROM FACTORIAL(5);
>
> IT SHOWING NULL VALUE...

FACT is NULL on declaration.  NULL (unknown) multiplied by anything is NULL.

--
Kevin Grittner
EDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

zzia88@gmail.com writes:
> CREATE OR REPLACE FUNCTION FACTORIAL(IN NUM BIGINT,OUT FACT BIGINT) AS $$
> DECLARE
>     FACT BIGINT;
>  BEGIN
>      FOR I IN REVERSE 1..NUM LOOP
>         FACT:=FACT*I;
>     END LOOP;
> END;
> $$ LANGUAGE plpgsql;

> SELECT* FROM FACTORIAL(5);

> IT SHOWING NULL VALUE...

Yes.  You didn't initialize FACT to something non-null (like, say, 1)
and multiplying null by anything will produce another null.

I think the REVERSE in your loop is wrong, too.

            regards, tom lane

zubair alam <zzia88@gmail.com> writes:
> CREATE OR REPLACE FUNCTION FACTORIAL(IN NUM BIGINT,OUT FACT BIGINT) AS $$
> DECLARE
> FACT BIGINT:=1;
>  BEGIN
>   FOR I IN REVERSE 1..NUM LOOP
> FACT:=FACT*I;
> END LOOP;
> END;
> $$ LANGUAGE plpgsql;

> if i am doing FACT BIGINT:=1; the also it giving the output NULL;

Well, the *third* bug in your function is that you're re-declaring
FACT as a local variable, thereby masking the output parameter.

            regards, tom lane