Kdjykuj

how can I get products where the value of a multiselect is not set ?

I've got these so far :

$filter =

    array(

      array('eq' => array("378")), //multiselect with one value

      array('eq' => array("378,379")), //multiselect with 2 values

      array('eq' => false), //multiselect with no value, need to make this work

);



$collection->addAttributeToFilter( "multiselect", $filter );

Try this:

$filter =

    array(

      array('eq' => array("378")), // multiselect with one value

      array('eq' => array("378,379")), // multiselect with 2 values

      array('null' => true), // multiselect with no value (null value)

);



$collection->addAttributeToFilter( "multiselect", $filter );

Update:

here is how it will work using the SearchCriteria with the product repository (tested on the custom attribute available_shipping_methods having a multiselect input type):

use MagentoCatalogApiProductRepositoryInterface;

use MagentoFrameworkApiFilterBuilder;

use MagentoFrameworkApiSearchFilterGroupBuilder;

use MagentoFrameworkApiSearchCriteriaBuilderFactory;

use MagentoFrameworkAppActionAction;

use MagentoFrameworkAppActionContext;

use MagentoFrameworkAppResponseInterface;



/**

 * Class Search

 */

class Search extends Action

{

    /**

     * @var ProductRepositoryInterface

     */

    private $productRepository;



    /**

     * @var SearchCriteriaBuilderFactory

     */

    private $searchCriteriaBuilderFactory;



    /**

     * @var FilterBuilder

     */

    private $filterBuilder;



    /**

     * @var FilterGroupBuilder

     */

    private $filterGroupBuilder;



    /**

     * Search constructor.

     *

     * @param Context $context

     * @param ProductRepositoryInterface $productRepository

     * @param SearchCriteriaBuilderFactory $searchCriteriaBuilderFactory

     * @param FilterBuilder $filterBuilder

     * @param FilterGroupBuilder $filterGroupBuilder

     */

    public function __construct(

        Context $context,

        ProductRepositoryInterface $productRepository,

        SearchCriteriaBuilderFactory $searchCriteriaBuilderFactory,

        FilterBuilder $filterBuilder,

        FilterGroupBuilder $filterGroupBuilder

    ) {

        parent::__construct($context);

        $this->productRepository            = $productRepository;

        $this->searchCriteriaBuilderFactory = $searchCriteriaBuilderFactory;

        $this->filterBuilder                = $filterBuilder;

        $this->filterGroupBuilder           = $filterGroupBuilder;

    }



    /**

     * Execute action based on request and return result

     *

     * Note: Request will be added as operation argument in future

     *

     * @return MagentoFrameworkControllerResultInterface|ResponseInterface

     * @throws MagentoFrameworkExceptionNotFoundException

     */

    public function execute()

    {

        try {

            $searchCriteriaBuilder = $this->searchCriteriaBuilderFactory->create();



            $filters = [

                $this->filterBuilder->setField('available_shipping_methods')

                                    ->setValue('%shipping_shipping%')

                                    ->setConditionType('like')

                                    ->create(),

                $this->filterBuilder->setField('available_shipping_methods')

                                    ->setValue('%flatrate_flatrate%')

                                    ->setConditionType('like')

                                    ->create(),

                $this->filterBuilder->setField('available_shipping_methods')

                                    ->setValue(null)

                                    ->setConditionType('null')

                                    ->create()

            ];



            $filterGroup = $this->filterGroupBuilder->setFilters($filters)

                                                    ->create();



            $searchCriteriaBuilder->setFilterGroups([$filterGroup]);

            $searchCriteria = $searchCriteriaBuilder->create();



            $productList = $this->productRepository->getList($searchCriteria);

        } catch (Exception $e) {

            $this->messageManager->addErrorMessage($e->getMessage());

        }



        $resultPage = $this->resultFactory->create($this->resultFactory::TYPE_PAGE);



        return $resultPage;

    }

}

Result query looks like this (our conditions at the last line):

SELECT `e`.*, IF(at_status.value_id > 0, at_status.value, at_status_default.value) AS `status`, IF(at_visibility.value_id > 0, at_visibility.value, at_visibility_default.value) AS `visibility`, IF(at_available_shipping_methods.value_id > 0, at_available_shipping_methods.value, at_available_shipping_methods_default.value) AS `available_shipping_methods`, `stock_status_index`.`stock_status` AS `is_salable` FROM `catalog_product_entity` AS `e`

 INNER JOIN `catalog_product_entity_int` AS `at_status_default` ON (`at_status_default`.`row_id` = `e`.`row_id`) AND (`at_status_default`.`attribute_id` = '97') AND `at_status_default`.`store_id` = 0

 LEFT JOIN `catalog_product_entity_int` AS `at_status` ON (`at_status`.`row_id` = `e`.`row_id`) AND (`at_status`.`attribute_id` = '97') AND (`at_status`.`store_id` = 1)

 INNER JOIN `catalog_product_entity_int` AS `at_visibility_default` ON (`at_visibility_default`.`row_id` = `e`.`row_id`) AND (`at_visibility_default`.`attribute_id` = '99') AND `at_visibility_default`.`store_id` = 0

 LEFT JOIN `catalog_product_entity_int` AS `at_visibility` ON (`at_visibility`.`row_id` = `e`.`row_id`) AND (`at_visibility`.`attribute_id` = '99') AND (`at_visibility`.`store_id` = 1)

 INNER JOIN `catalog_product_entity_text` AS `at_available_shipping_methods_default` ON (`at_available_shipping_methods_default`.`row_id` = `e`.`row_id`) AND (`at_available_shipping_methods_default`.`attribute_id` = '265') AND `at_available_shipping_methods_default`.`store_id` = 0

 LEFT JOIN `catalog_product_entity_text` AS `at_available_shipping_methods` ON (`at_available_shipping_methods`.`row_id` = `e`.`row_id`) AND (`at_available_shipping_methods`.`attribute_id` = '265') AND (`at_available_shipping_methods`.`store_id` = 1)

 INNER JOIN `cataloginventory_stock_status` AS `stock_status_index` ON e.entity_id = stock_status_index.product_id WHERE (((IF(at_available_shipping_methods.value_id > 0, at_available_shipping_methods.value, at_available_shipping_methods_default.value) LIKE '%shipping_shipping%') OR (IF(at_available_shipping_methods.value_id > 0, at_available_shipping_methods.value, at_available_shipping_methods_default.value) LIKE '%flatrate_flatrate%') OR (IF(at_available_shipping_methods.value_id > 0, at_available_shipping_methods.value, at_available_shipping_methods_default.value) IS NULL))) AND (e.created_in <= 1) AND (e.updated_in > 1)

and result itself contains products with desired attribute value and without value at all (null).

PS: a comma-separated value of the multiselect attribute is the main problem, because of that we need to use %LIKE% condition, what is not a good idea.