public function from($from)
    {
        $pos = strpos($from, ' ');
        if (false !== $pos) {
            $this->table = substr($from, 0, $pos);
        } else {
            $this->table = $from;
        }
        $this->fullTable = $this->db->getTable($this->table);
        return $this->add('from', $this->db->getTable($from));
    }