Re: Sum() rows

lucas(at)presserv(dot)org wrote:
> Hi.
> How can I sum a row and show the sum for each row???
> For example, in a finances table that have the total movimentation(debit/credit)
> in the bank.
>
> i.e:
> CREATE TABLE TB1 (id integer primary key, value numeric);
> insert into tb1 values (1,20);
> insert into tb1 values (2,2);
> insert into tb1 values (3,3);
> insert into tb1 values (4,17);
> insert into tb1 values (5,-0.5);
> insert into tb1 values (6,3);
>
> I want a query that returns:
> -id- | --- value --- | --- subtot ---
> 1 | 20.00 | 20.00
> 2 | 2.00 | 22.00
> 3 | 3.00 | 25.00
> 4 | 17.00 | 42.00
> 5 | -0.50 | 41.50
> 6 | 3.00 | 44.50
>
> The subtot colum will be the "prev. subtot colum"+"value colum". :-/
> I dont know how to make the "subtot" colum, I tried to use the sum() function
> but it not works correctly.
> Any idea???
>
> Thanks.
>
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CREATE TABLE tb1 (id integer primary key, value numeric);

CREATE TYPE subtotal_type AS (id integer, value numeric, subtotal numeric);

CREATE OR REPLACE FUNCTION subtotal () RETURNS SETOF subtotal_type AS $$
DECLARE
tbrow RECORD;
sbrow subtotal_type;
BEGIN
sbrow.subtotal := 0;
FOR tbrow IN
SELECT id, value FROM tb1 ORDER BY id
LOOP
sbrow.id := tbrow.id;
sbrow.value := tbrow.value;
sbrow.subtotal := sbrow.subtotal + tbrow.value;
RETURN NEXT sbrow;
END LOOP;
RETURN;
END;
$$ LANGUAGE plpgsql;

insert into tb1 (id, value) values (1, 20.0);
insert into tb1 (id, value) values (2, 2.0);
insert into tb1 (id, value) values (3, 3.0);

select * from subtotal();