Philip Hallstrom wrote:
>
> Also... is there any reason you don't just do:
>
> SELECT MAX(id) FROM article
>
> rather than what you have below? It would get you the same thing wouldn't
> it and save a query...
>
> On Thu, 3 May 2001, Chris Ryan wrote:
>
> > Jason,
> >
> > Look into the pg_result() function. You would use it something like
> > this:
> >
> > $q = pg_Exec("SELECT id FROM article WHERE id=(SELECT MAX(id) FROM
> > article)");
> > $maxid = pg_result($q,0,0); # pg_result($result,$row,$column_num)
> > echo "The highest id is ". $maxid[0];
> >
> > Hope this helps.
> >
> > Chris Ryan
> > chris@greatbridge.com
> >
> > Jason wrote:
> > >
> > > Hi, I want to try and optimize my calls to postgreSQL from PHP. If
> > > I only need one field from a select statement, what should I use? I am
> > > currently using:
> > > $q = pg_Exec("SELECT id FROM article WHERE id=(SELECT MAX(id)
> > > FROM article)");
Or even more efficiently:
SELECT id FROM article ORDER BY id DESC LIMIT 1;
Since that will use an index on article.id if article is a big table, has been
vacuum analyzed, and has an index available.
Regards,
Andrew.
--
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Andrew McMillan, e-mail: Andrew@catalyst.net.nz
Catalyst IT Ltd, PO Box 10-225, Level 22, 105 The Terrace, Wellington
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