protected function get_column_value_grouped_products( $product ) {
		if ( 'grouped' !== $product->get_type() ) {
			return '';
		}

		$grouped_products = array();
		$child_ids        = $product->get_children( 'edit' );
		foreach ( $child_ids as $child_id ) {
			$child = wc_get_product( $child_id );
			if ( ! $child ) {
				continue;
			}

			$grouped_products[] = $child->get_sku( 'edit' ) ? $child->get_sku( 'edit' ) : 'id:' . $child_id;
		}
		return $this->implode_values( $grouped_products );
	}