public function getRawSql()
    {
        $search = array();
        $replace = array();
        $params = $this->getParams();
        ksort($params, SORT_STRING);
        foreach ($params as $key => $value) {
            if (is_int($key)) {
                $key = '?';
            }
            $search[] = $key;
            if (is_string($value)) {
                $value = "'$value'";
            }
            $replace[] = $value;
        }
        return str_replace($search, $replace, $this->getSql());
    }