How to connect MySQL db using new XAMPP

Question

What is the best way to connect and query in MySQL using XAMPP? And please tell me how to  implement PDO in the below script.

<?php
    $key = $_GET['key'];
    $array = array();
    $con = mysql_connect("localhost", "root", "");
    $db = mysql_select_db("search", $con);

    $query = mysql_query("select * from ajax_example where name LIKE '%{$key}%'");

    while ($row = mysql_fetch_assoc($query)) {
        $array[] = $row['name'];
    }
    echo json_encode($array);
?>