Get MySQL error code with Doctrine DBAL

gistfile1.php

<?php

$sql = '...';

$stmt = $conn->prepare($sql);

try {
    $stmt->execute();
} catch (\Doctrine\DBAL\DBALException $e) {
    $previous = $e->getPrevious();
    if ($previous instanceof \Doctrine\DBAL\Driver\Mysqli\MysqliException) {
        // $errorCode contains MySQL error code (ex: 1062 for a duplicate entry)
        $errorCode = $previous->getCode();
    }
}