PHP - how to make MySQL select query with PDO?

<?php

​

    if(isset($_GET['role']))

    {

        $role = $_GET['role'];

​

        $db_name = 'test';

        $db_host = '127.0.0.1'; // 'localhost'

        $db_username = 'root';

        $db_password = 'root';

​

        $dsn = 'mysql:dbname=' . $db_name . ';host=' . $db_host . ';charset=utf8';

        $pdo = new PDO($dsn, $db_username, $db_password);

        $statement = $pdo->prepare('SELECT * FROM `users` WHERE `role` = :role');

​

        if($statement === FALSE)

            die('Query preparation error!');

​

        $parameters = array(

            'role' => $role

        );

​

        if($statement->execute($parameters))

        {

            echo '<pre>';

            echo "[ID]\t[name]\t[role]<br />";

​

            while ($row = $statement->fetch(PDO::FETCH_OBJ))

            {

                //echo print_r($row, true);

                echo $row->id . "\t" . $row->name . "\t" . $row->role . '<br />';

            }

            echo '</pre>';

        }

        else

            echo 'Query execution error!';

    }

​

?>

CREATE TABLE `users` (

    `id` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT,

    `name` VARCHAR(100) NOT NULL,

    `role` VARCHAR(15) NOT NULL,

    PRIMARY KEY (`id`)

)

ENGINE=InnoDB;

INSERT INTO `users`

    (`name`, `role`)

VALUES

    ('John', 'admin'),

    ('Chris', 'moderator'),

    ('Kate', 'user'),

    ('Denis', 'moderator');