/**
* Creates a command for execution.
* @param string $sql the SQL statement to be executed
* @param array $params the parameters to be bound to the SQL statement
* @return Command the Sphinx command
*/
public function createCommand($sql = null, $params = [])
{
$command = new Command(['db' => $this, 'sql' => $sql]);
return $command->bindValues($params);
}