[PHP] psql with PHP question

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];
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?  Thank
you.
Jason