Re: newbie sql question: select every day another quote

From: Tod McQuillin <devin(at)spamcop(dot)net>
To: Janning Vygen <vygen(at)planwerk6(dot)de>
Cc: Len Morgan <len-morgan(at)crcom(dot)net>, PostgreSQL-General <pgsql-general(at)postgresql(dot)org>
Subject: Re: newbie sql question: select every day another quote
Date: 2001-05-12 13:30:00
Message-ID: Pine.GSO.4.31.0105120826360.1166-100000@sysadmin
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On Sat, 12 May 2001, Janning Vygen wrote:

> Am Samstag, 12. Mai 2001 14:37 schrieb Len Morgan:
> > The "no result part" is harder. You'll have to have some sort of client
> > program that can tell you if the above quote returned a row or not. Once
> > you have that, if the above query did NOT return a row, you can use the
> > following two steps:
> >
> > UPDATE quotes SET lastdayshown = now():: WHERE oid = (SELECT oid FROM
> > quotes WHERE lastdayshown IS NULL LIMIT 1) ;
>
> i managed this now in php. works fine
> but the idea was to put this structure into the database, so the db user just
> have to send one select and once a day there is an automagical update.

It will probably work to make a plpgsql function doing something like:

1. Figure out the primary key of today's quote
2. Update the database if necessary
3. Return the key of today's quote

then you can SELECT * from quotes WHERE key = todays_key();
--
Tod McQuillin

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