Retrieving a Value with the fetchColumn() Method

The fetchColumn() method returns a single column value from the next row of a result set. If you do not specify the column, it defaults to returning the first column (index 0). This method is extremely convenient when executing queries that return only a single piece of data, such as counting records (COUNT) or fetching a specific field for an individual user.

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 getUserEmail($id) {
        $statement = $this->connection->prepare("SELECT email FROM users WHERE id = :id");
        $statement->execute(['id' => $id]);
        
        // fetchColumn() returns a string directly
        $email = $statement->fetchColumn();
        
        $statement->closeCursor();
        return $email;
    }
}

// PART 3: Usage
$db = new Database();
$email = $db->getUserEmail(1);

if ($email) {
    echo "The email address of the user with ID 1 is: " . $email;
}
?>

RESULT

The result will be displayed here...

Practical Application: We use the fetchColumn method when we want to shorten the code and avoid working with associative arrays, as we obtain the raw value (string or number) directly. 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 with test data exists within the pdo_db database.
The method returns the column value directly; if there are no more rows, it returns false.
Insert the example below into a PHP file and observe how quickly you retrieve the user's email.