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	from "Pham, Thinh" at Aug 16, 99 11:02:20 am
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Date: Tue, 17 Aug 1999 14:05:02 +0300
To: "tjk@tksoft.com" <tjk@tksoft.com>, tpham@mail.priority.net (Pham Thinh)
From: Herouth Maoz <herouth@oumail.openu.ac.il>
Subject: Re: [SQL] datediff function
Cc: pgsql-sql@postgreSQL.org

At 02:26 +0300 on 17/08/1999, tjk@tksoft.com wrote:


>
> I think what you are looking for is age()
> E.g.
>
> "update schedule set purged = 0 where age('now',dayin) > timespan('30
>days'::reltime)"
>
> Presuming a table such as this:
>
> create table schedule (purged int, dayin datetime);
>
> This replaces "day" and "timein" with "dayin."

Basically correct, but if there is an index on dayin, it won't be used. The
best query to do would be

WHERE dayin > 'now'::datetime - '30 days'::timespan;

Herouth

--
Herouth Maoz, Internet developer.
Open University of Israel - Telem project
http://telem.openu.ac.il/~herutma