[BurtonTech]

Not sure if this is the best solution, but it works for MySQLi:

//Get the Connection info from X-Cart 5
$xc_conn = \XLite\Core\Database::getEM()->getConnection();

//Collect the info you need for a MySQLi connection
$sql_host =$xc_conn->getHost();
$sql_db =$xc_conn->getDatabase();
$sql_user =$xc_conn->getUsername();
$sql_password =$xc_conn->getPassword();

//Collect your data using MySQLi
$conn = new mysqli($sql_host, $sql_user, $sql_password,$sql_db);

if ($conn->connect_error) {
    error_log('MySQLi could not connect: ' . $conn->connect_error);
}
	
$sql_query = "SELECT * FROM YourTable";

$db_results = $conn->query($sql_query);

$results_array = $db_results->fetch_assoc();

if ($db_results->num_rows > 0) {
    foreach($results_array  as $dbkey=>$dbvalue) {
        echo 'Key: '.$dbkey.' = '.$dbvalue.'<br />';
    }
}

Hope that helps!