From: | "hubert depesz lubaczewski" <depesz(at)gmail(dot)com> |
---|---|
To: | emilu(at)encs(dot)concordia(dot)ca |
Cc: | pgsql-sql-owner(at)postgresql(dot)org, "pgsql general list" <pgsql-general(at)postgresql(dot)org> |
Subject: | Re: Date for a week day of a month |
Date: | 2007-07-04 08:58:01 |
Message-ID: | 9e4684ce0707040158w3573972ev412263bb11ebe3d4@mail.gmail.com |
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Thread: | |
Lists: | pgsql-general |
On 7/3/07, Emi Lu <emilu(at)encs(dot)concordia(dot)ca> wrote:
>
> Can I know how to get the date of each month's last Thursday please?
> Query: select getDateBaseOnWeekday('2007-04-01', 'Last Thursday');
> Result: 2007-04-26
>
you can easily do it without functions.
for example, this select:
SELECT
cast(d.date + i * '1 day'::interval as date)
FROM
(select '2007-04-01'::date as date) d,
generate_series(0, 30) i
WHERE
to_char(d.date, 'MM') = to_char( cast(d.date + i * '1 day'::interval as
date), 'MM')
AND to_char(cast(d.date + i * '1 day'::interval as date), 'D') = '5'
ORDER BY 1 DESC
LIMIT 1
;
does what you need.
to get last-thursday for another month, just change: (select
'2007-04-01'::date as date) d, to be 1st of any other month.
depesz
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