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Re: psql with PHP question

From: Jason <gee308(at)mediaone(dot)net>
To: Tod McQuillin <devin(at)spamcop(dot)net>
Cc: pgsql-php(at)postgresql(dot)org
Subject: Re: psql with PHP question
Date: 2001-05-03 13:43:44
Message-ID: 3AF16090.69AB7A8@mediaone.net (view raw or flat)
Thread:
Lists: pgsql-generalpgsql-novicepgsql-php
Thanks, I'll use that function.  I also didn't realize the second select
statement was unnecessary.
Jason
Tod McQuillin wrote:

> On Thu, 3 May 2001, 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)");
> > $maxid = pg_fetch_array($q, 0);
> > echo "The highest id is ". $maxid[0];
>
> Your select statement is the same thing as simply
>
>         SELECT max(id) FROM article
>
> There is no reason that I can see to use the subselect unless you're
> interested in multiple matching rows or other columns (which it appears
> that you are not).
>
> > What can I use besides an array to get a single value? In general, using
> > a single variable always saves more memory than using an array?
>
> Don't worry about saving memory.  All your variables are dynamically
> allocated and cleaned up automatically when no longer needed.
>
> To fetch a single value from a select statement, I use a function like
> this one:
>
> function pg_fetch ($conn, $sql) {
>   $q = pg_exec($conn, $sql);
>   if (pg_numrows($q) > 0) {
>     return pg_result($q, 0, 0);
>   } else {
>     return "";
>   }
> }
>
> You can declare the function on a separate file if you'll use it from
> multiple php scripts and then use require_once("functions.php") from each
> script that uses it.
>
> Calling it is as easy as:
>
>         $maxid = pg_fetch($conn, "SELECT max(id) FROM article");
>
> Hope this helps.
> --
> Tod McQuillin


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