public function getSelectionAlias($column)
        {
            if (!is_numeric($column) && !is_string($column)) {
                if (is_array($column) && array_key_exists('column', $column)) {
                    $column = $column['column'];
                } else {
                    throw new Exception('Invalid column!');
                }
            }
            if (!isset($this->aliases[$column])) {
                $this->aliases[$column] = str_replace('.', '_', $column);
            }

            return $this->aliases[$column];
        }