Обсуждение: Arithmetic operation on DATE

is it possible to add a date datatype column to a number resulting to a
date......


theoretically it should do this,,,

X is in months

date + X = date

-->  2001-08-20 + 6 = 2002-02-20

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On Mon, 13 Aug 2001 21:48, macky wrote:
> is it possible to add a date datatype column to a number resulting to a
> date......

chris=# select date(CURRENT_TIMESTAMP);
    date
------------
 2001-08-13
(1 row)

chris=# select date(CURRENT_TIMESTAMP) + '6 @days'::interval;
        ?column?
------------------------
 2001-08-19 00:00:00+12
(1 row)

chris=# select date(date(CURRENT_TIMESTAMP) + '6 @days'::interval);
    date
------------
 2001-08-19
(1 row)

That what you want?

> theoretically it should do this,,,
>
> X is in months
>
> date + X = date
>
> -->  2001-08-20 + 6 = 2002-02-20
>
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On Mon, Aug 13, 2001 at 05:48:57PM +0800, macky wrote:
> is it possible to add a date datatype column to a number resulting to a
> date......
>
>
> theoretically it should do this,,,
>
> X is in months
>
> date + X = date
>
> -->  2001-08-20 + 6 = 2002-02-20

test=# select '2001-08-20'::date + '6months'::interval;
        ?column?
------------------------
 2002-02-20 00:00:00+01
(1 row)


 ..see docs about the "interval" datetype.

            Karel

--
 Karel Zak  <zakkr@zf.jcu.cz>
 http://home.zf.jcu.cz/~zakkr/

 C, PostgreSQL, PHP, WWW, http://docs.linux.cz, http://mape.jcu.cz

I know you can do it for days, thus:

   expires = CURRENT_TIMESTAMP + 10

would be 10 days from now. Don't know about months though.

HTH
--
Jason Wong
Gremlins Associates
www.gremlins.com.hk


----- Original Message -----
From: macky <macky@edsamail.com>
To: <pgsql-novice@postgresql.org>; <pgsql-sql@postgresql.org>
Sent: Monday, August 13, 2001 5:48 PM
Subject: [NOVICE] Arithmetic operation on DATE


> is it possible to add a date datatype column to a number resulting to a
> date......
>
>
> theoretically it should do this,,,
>
> X is in months
>
> date + X = date
>
> -->  2001-08-20 + 6 = 2002-02-20
>