public function applyCategory()
    {
        $this->joinCategoryData();
        $this->removeAdditionalTableDuplicateFields();
        $this->getSelect()->columns($this->getAdditionalColumns());

        $subSelect = new \Zend_Db_Expr(sprintf("(%s)", (string) $this->getSelect()));

        $this->_select = $this->getConnection()->select()->from($subSelect);

        return $this;
    }