PHP PDO lastInsertId - Last Inserted ID

Last Inserted ID (LAST INSERT ID)

When we insert a new record into a table using AUTO_INCREMENT, the database automatically generates a new unique ID. The lastInsertId() method allows us to retrieve this number immediately and use it further in our application.

EXAMPLE

<?php
$server = "localhost";
$username = "root";
$password = "";
$database = "pdo_database";

try {
    $dsn = "mysql:host=$server;dbname=$database;charset=utf8mb4";
    $connection = new PDO($dsn, $username, $password);
    $connection->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

    // Inserting a single new user into the table
    $sql = "INSERT INTO users (first_name, last_name, email) VALUES ('Thomas', 'Brown', 'thomas@example.com')";

    $connection->exec($sql);
    
    // IMPORTANT FOR BEGINNERS: The lastInsertId() method works at the connection level.
    // It returns the ID of the last inserted row (auto-increment value) that was
    // created in this connection. Since we inserted only one row, we get its ID.
    $last_id = $connection->lastInsertId();
    
    echo "New record inserted. The ID of the last inserted user is: " . $last_id;
} catch (PDOException $e) {
    echo "Error: " . $e->getMessage();
}

// Closing the connection
$connection = null;
?>

RESULT

The result will be displayed here...

In the example above, we inserted 5 additional people into the users table (totaling 10). The method will return the number 10, confirming the ID of the last successfully inserted record.

The method is called directly on the PDO connection object.

Useful when creating related tables (e.g., when you need a user ID to enter their address).

Returns the ID of the last row inserted during the current connection session.