Executing Statements with the query() Method

The query() method executes an SQL statement in a single step and returns the result set as a PDOStatement object. Unlike the prepare() method, queries here are not pre-compiled, making it ideal for simple SELECT commands that contain no user-supplied data (e.g., listing categories or system settings). It is faster and requires shorter syntax since it bypasses a separate call to the execute() method.

EXAMPLE

<?php
class Database {
    private $server = "localhost";
    private $username = "root";
    private $password = "";
    private $db_name = "pdo_db";
    public $connection;

    public function __construct() {
        try {
            // Added charset=utf8mb4 for character support
            $dsn = "mysql:host=" . $this->server . ";dbname=" . $this->db_name . ";charset=utf8mb4";
            $this->connection = new PDO($dsn, $this->username, $this->password);
            $this->connection->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
        } catch(PDOException $e) {
            die("Connection failed: " . $e->getMessage());
        }
    }

    public function printAll() {
        // The query method returns results immediately
        $sql = "SELECT first_name, last_name FROM users";
        
        foreach ($this->connection->query($sql) as $row) {
            echo "User: " . $row['first_name'] . " " . $row['last_name'] . "<br>";
        }
    }
}

// PART 3: Usage
$db = new Database();
$db->printAll();
?>

RESULT

The result will be displayed here...

Practical Application: Use the query method only when the SQL statement is predetermined and safe from outside manipulation. Check the process at home by following these steps:

Start the Apache and MySQL modules in the XAMPP control panel.
Ensure via phpMyAdmin that the users table exists and contains data within the pdo_db database.
The method immediately returns an object with results that can be traversed using a foreach loop.
Insert the example below into a PHP file and check the quick listing of all users.