public function toSQL(Parameters $params, bool $inner_clause)
    {
        $drv = $params->getDriver();

        $lhs = $this->getLHS() === null ? null : $drv->toSQL($params, $this->getLHS(), true);
        $rhs = $drv->toSQL($params, $this->getRHS(), true);

        $op = $this->getOperator();
        if ($lhs !== null)
        {
            $sql = $lhs . ' ' . $op . ' ' . $rhs;
            if ($inner_clause)
                return '(' . $sql . ')';
            return $sql;
        }
        
        return $op . ' ' . $rhs;
    }