protected function _prepareCollection()
    {
        $store = $this->getStore();
        $collection = $this->productFactory->create()
            ->getCollection()
            ->addAttributeToSelect('sku')
            ->addAttributeToSelect('name')
            ->addAttributeToSelect('attribute_set_id')
            ->addAttributeToSelect('type_id')
            ->setStore($store);

        if ($this->moduleManager->isEnabled('Magento_CatalogInventory')) {
            $collection->joinField(
                'qty',
                'cataloginventory_stock_item',
                'qty',
                'product_id=entity_id',
                '{{table}}.stock_id=1',
                'left'
            );
        }

        if ($store->getId()) {
            $collection
                ->addStoreFilter($store)
                ->joinAttribute(
                    'name',
                    'catalog_product/name',
                    'entity_id',
                    null,
                    'inner',
                    Store::DEFAULT_STORE_ID
                )
                ->joinAttribute(
                    'custom_name',
                    'catalog_product/name',
                    'entity_id',
                    null,
                    'inner',
                    $store->getId()
                )
                ->joinAttribute(
                    'status',
                    'catalog_product/status',
                    'entity_id',
                    null,
                    'inner',
                    $store->getId()
                )
                ->joinAttribute(
                    'visibility',
                    'catalog_product/visibility',
                    'entity_id',
                    null,
                    'inner',
                    $store->getId()
                )
                ->joinAttribute(
                    'price',
                    'catalog_product/price',
                    'entity_id',
                    null,
                    'left',
                    $store->getId()
                );
        } else {
            $collection
                ->addAttributeToSelect('price')
                ->joinAttribute(
                    'status',
                    'catalog_product/status',
                    'entity_id',
                    null,
                    'inner'
                )
                ->joinAttribute(
                    'visibility',
                    'catalog_product/visibility',
                    'entity_id',
                    null,
                    'inner'
                );
        }

        $collection
            ->addAttributeToFilter(
                'creator_id',
                ['neq' => null]
            )
            ->joinTable(
                $collection->getTable('customer_entity'),
                'entity_id = creator_id',
                [
                    'vendor_email' => 'email'
                ]
            );


        $subquery = new \Zend_Db_Expr("( SELECT entity_id, SUBSTRING_INDEX(value, ',', 1) AS num1 FROM catalog_product_entity_varchar where catalog_product_entity_varchar.attribute_id = 200
        UNION DISTINCT
        SELECT entity_id, SUBSTRING_INDEX(value, ',', -1) FROM catalog_product_entity_varchar where catalog_product_entity_varchar.attribute_id = 200
        )");

        $collection->getSelect()->joinInner(
            array('vtable' => $subquery),
            'vtable.entity_id = `e`.`entity_id`',
            [
                "vendorId" => "CONCAT(`e`.`entity_id`, '_', vtable.num1)"
            ]
        );

        $this->setCollection($collection);

        $this->getCollection()->addWebsiteNamesToResult();

        return parent::_prepareCollection();
    }

Happy Coding…