Re: Generating Rows from a date and a duration

On 09/08/2010 08:24 AM, Tim Schumacher wrote:
>>> I'm kinda stuck situation, I have a timestamp which resambles a
>>> startdate and a duration in days and I want to bloat this, so I have a
>>> row for every day beginning from the startdate. I have created an
>>> example bellow, maybe I'm doing it on the wrong angle and you can come
>>> up with some better ideas:

<snip>

> As you can see in my example, I'm already using it and this is my
> dilemma. Since I can not bring the values of the FROM-Table to the
> parameters of my function.

Depending on how large your base table is, this might work for you:

CREATE TABLE example
(
id serial NOT NULL,
startdate timestamp without time zone,
duration int NOT NULL,
CONSTRAINT pq_example_id PRIMARY KEY (id)
);

insert into example(id,startdate,duration) values (1,'2010-09-03',4);
insert into example(id,startdate,duration) values (2,'2010-09-03',6);

CREATE OR REPLACE FUNCTION unroll_durations()
RETURNS TABLE(
example_id integer,
duration_date date)
AS $$
DECLARE
rec1 record;
rec2 record;
BEGIN
FOR rec1 IN SELECT id, startdate, duration
FROM example
LOOP
FOR rec2 IN SELECT
to_date(to_char(rec1.startdate,'YYYY-MM-DD'),'YYYY-MM-DD') + s.a as
stockdate
FROM generate_series(0, rec1.duration - 1) AS s(a)
LOOP
example_id := rec1.id;
duration_date := rec2.stockdate;
RETURN NEXT;
END LOOP;
END LOOP;
END;
$$ LANGUAGE plpgsql;

select * from unroll_durations();
example_id | duration_date
------------+---------------
1 | 2010-09-03
1 | 2010-09-04
1 | 2010-09-05
1 | 2010-09-06
2 | 2010-09-03
2 | 2010-09-04
2 | 2010-09-05
2 | 2010-09-06
2 | 2010-09-07
2 | 2010-09-08
(10 rows)

HTH,

Joe

--
Joe Conway
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