private function getSelectQuery()
    {
        return 'SELECT '.(empty($this->parts['select']) ? '*' : implode(', ', $this->parts['select'])).
               ' FROM '.$this->getFromClause().
               (($this->parts['where'] !== null) ? ' WHERE '.$this->parts['where'] : null).
               (!empty($this->parts['group_by']) ? ' GROUP BY '.implode(', ', $this->parts['group_by']) : null).
               (($this->parts['having'] !== null) ? ' HAVING '.$this->parts['having'] : null).
               (!empty($this->parts['order_by']) ? ' ORDER BY '.implode(', ', $this->parts['order_by']) : null).
               (($this->parts['limit'] !== null) ? ' LIMIT '.$this->parts['limit'] : null).
               (($this->parts['offset'] !== null) ? ' OFFSET '.$this->parts['offset'] : null);
    }