public function getSelect()
    {
        $concat = null;

        foreach ($this->fieldDescriptors as $fieldDescriptor) {
            if (null == $concat) {
                $concat = $fieldDescriptor->getSelect();
            } else {
                $concat = 'CONCAT(' . $concat . ', CONCAT(\'' . $this->glue . '\', ' . $fieldDescriptor->getSelect() . '))';
            }
        }

        return $concat;
    }