php存储过程输出参数

<!--
create procedure in_out (in parameter integer)
begin
declare variable varchar(20);
if parameter=1 then
set variable='MySQL';
else
set variable='PHP';
end if;
insert into userinfo(username) values (variable);
end;

-->

<!--

create procedure outstatement(out str varchar(50))
begin
set str="hello the world!";
end ;

-->
<?php
define('CLIENT_MULTI_RESULTS',131072);
$host="localhost";
$user="root";
$password="";
$id=$_REQUEST["id"];
$cxn = mysql_connect($host,$user,$password,1,CLIENT_MULTI_RESULTS) or die("Could not connect: ".mysql_error());
$db=mysql_select_db("test");
$res=mysql_query("call outstatement(@str)",$cxn); 
$res=mysql_query("select @str",$cxn); 
$row=mysql_fetch_row($res);
echo $row[0];
?>