function ToString()
    {
        $resultArr = array((string)$this->tables[0]);
        foreach ($this->tables as $key=>$table)
        {
            if ($key == 0)
                 continue;
                
            $part = (string)$this->joins[$key - 1]; 
            $part .= ' ' . (string)$table;
            $part .= ' ON ' . (string)$this->conditions[$key - 1];

            $resultArr[] = $part;
        }
        return join(' ', $resultArr);
    }