Re: temporal variants of generate_series()

Here's a shorter version:

On the date variant, I wasn't sure how to handle intervals with parts
smaller than days:
floor, ceiling, round or error out
To get round, the last parameters of generate_series would be
extract('epoch' FROM '1 day'::interval)::bigint * round(extract('epoch' FROM
$3) / extract('epoch' FROM '1 day'::interval))::bigint

CREATE OR REPLACE FUNCTION generate_series (
start_ts timestamptz,
end_ts timestamptz,
step interval
) RETURNS SETOF timestamptz
STRICT
LANGUAGE sql
AS $$
SELECT
'epoch'::timestamptz + s.i * '1 second'::interval AS "generate_series"
FROM
generate_series(
extract('epoch' FROM $1)::bigint,
extract('epoch' FROM $2)::bigint,
extract('epoch' FROM $3)::bigint
) s(i);
$$;

CREATE OR REPLACE FUNCTION generate_series (
start_ts date,
end_ts date,
step interval
) RETURNS SETOF date
STRICT
LANGUAGE sql
AS $$
SELECT
('epoch'::date + s.i * '1 second'::interval)::date AS "generate_series"
FROM
generate_series(
extract('epoch' FROM $1)::bigint,
extract('epoch' FROM $2)::bigint,
extract('epoch' FROM date_trunc('day', $3))::bigint -- does a floor
) s(i);
$$;

Jean-Pierre Pelletier
e-djuster