SUM i SQL og id

<?php
function get_connection() {
    $con = new PDO('mysql:host=localhost;dbname=Test', 'root', '');
    $con->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    $con->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_ASSOC);
    return $con;
}

function two() {
    $con = get_connection();
    $stmt = $con->prepare('SELECT SUM(f1) AS sum FROM T1 WHERE f2 >= :f2');
    $stmt->execute(array(':f2' => 'C'));
    $row = $stmt->fetch();
    $sum = $row['sum'];
    echo "sum = $sum\r\n";
    echo "f2 =";
    $stmt = $con->prepare('SELECT f2 FROM T1 WHERE f2 >= :f2');
    $stmt->execute(array(':f2' => 'C'));
    while($row = $stmt->fetch()) {
        $f2 = $row['f2'];
        echo " $f2";
    }
    echo "\r\n";
}

function multi() {
    $con = get_connection();
    $stmt = $con->prepare('SELECT SUM(f1) AS sum FROM T1 WHERE f2 >= :f2; SELECT f2 FROM T1 WHERE f2 >= :f2');
    $stmt->execute(array(':f2' => 'C'));
    $row = $stmt->fetch();
    $sum = $row['sum'];
    echo "sum = $sum\r\n";
    echo "f2 =";
    $stmt->nextRowSet();
    while($row = $stmt->fetch()) {
        $f2 = $row['f2'];
        echo " $f2";
    }
    echo "\r\n";
}

/*

DELIMITER //
CREATE PROCEDURE sp_two(_f2 varchar(50))
BEGIN
SELECT SUM(f1) AS sum FROM T1 WHERE f2 >= _f2;
SELECT f2 FROM T1 WHERE f2 >= _f2;
END//
DELIMITER ;

*/
function sp() {
    $con = get_connection();
    $stmt = $con->prepare('CALL sp_two(?)');
    $arg = 'C';
    $stmt->bindParam(1, $arg, PDO::PARAM_STR);
    $stmt->execute();
    $row = $stmt->fetch();
    $sum = $row['sum'];
    echo "sum = $sum\r\n";
    echo "f2 =";
    $stmt->nextRowSet();
    while($row = $stmt->fetch()) {
        $f2 = $row['f2'];
        echo " $f2";
    }
    echo "\r\n";
}

function union() {
    $con = get_connection();
    $stmt = $con->prepare('(SELECT CAST(SUM(f1) AS CHAR) AS sumorf2 FROM T1 WHERE f2 >= :f2) UNION (SELECT f2 AS sumorf2 FROM T1 WHERE f2 >= :f2)');
    $stmt->execute(array(':f2' => 'C'));
    $first = true;
    while($row = $stmt->fetch()) {
        if($first) {
            $sum = $row['sumorf2'];
            echo "sum = $sum\r\n";
            $first = false;
            echo "f2 =";
        } else {
            $f2 = $row['sumorf2'];
            echo " $f2";
        }
    }
    echo "\r\n";
}

two();
multi();
sp();
union();
?>