Get All Category IDs from Product Collection in Magento 2<\/p>\n\n\n\n
Today I will explain how you can retrieve all category IDs for every product from the product collection in Magento 2 in this article.<\/p>\n\n\n\n
So, at first, we will get a collection of products with filters and some product IDs. You can write the code anywhere according to your requirements and can apply any filter to it. I have written the code in the module’s helper file.<\/p>\n\n\n\n
After that, we will call the addCategoryIds() function from the collection, which will add the ‘category_ids’ array to the collection for every product which will contain all category IDs associated with that product. Look at the code below:<\/p>\n\n\n\n
<?php\nnamespace Company\\Module\\Helper;\n\nuse Magento\\Catalog\\Model\\ResourceModel\\Category\\CollectionFactory;\n\nclass Data extends \\Magento\\Framework\\App\\Helper\\AbstractHelper\n{\n \/**\n * @var \\Magento\\Catalog\\Model\\ResourceModel\\Product\\CollectionFactory\n *\/\n private $productCollection;\n\n public function __construct(\n \\Magento\\Catalog\\Model\\ResourceModel\\Product\\CollectionFactory $productCollection\n ) {\n parent::__construct($context);\n $this->productCollection = $productCollection;\n }\n\n public function getProductCollection()\n {\n $productIds = [1,2,3,4];\n $collection = $this->productCollection->create()\n ->addAttributeToSelect('*')\n ->addStoreFilter()\n ->addFieldToFilter(\n 'entity_id',\n ['in' => $productIds]\n )\n ->addCategoryIds(); \/\/ the main function to get all category ids\n foreach ($collection as $product) {\n print_r($product->getCategoryIds());\n\n }\n }\n}<\/pre>\n\n\n\nBy printing the above collection data, you must be getting ‘category_ids’<\/strong><\/em> as the key with an array of category ids. But if in case you are not getting the ‘category_ids’<\/strong><\/em> value from the above\u00a0collection then you can create after<\/strong> plugin for the function addCategoryIds()<\/strong> as below:<\/p>\n\n\n\nIn your module’s di.xml<\/span> file write the following code :<\/p>\n\n\n\n<config xmlns:xsi="http:\/\/www.w3.org\/2001\/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager\/etc\/config.xsd">\n <type name="Magento\\Catalog\\Model\\ResourceModel\\Product\\Collection">\n <plugin name="Company_Module::productcollection" type="Company\\Module\\Model\\Plugin\\Productcollection" sortOrder="1" \/>\n <\/type>\n<\/config><\/pre>\n\n\n\nNow create a file Productcollection.php<\/strong> for the plugin under\u00a0the path as mentioned above, i.e.\u00a0Company\\Module\\Model\\Plugin\\,<\/strong>\u00a0and write the below code in the file :<\/p>\n\n\n\n<?php\nnamespace Company\\Module\\Model\\Plugin;\n\nclass Productcollection\n{\n public function afterAddCategoryIds(\n \\Magento\\Catalog\\Model\\ResourceModel\\Product\\Collection $subject,\n $result\n ) {\n if ($subject->getFlag('category_ids_added')) {\n return $subject;\n }\n $ids = array_keys($subject->getItems());\n if (empty($ids)) {\n return $subject;\n }\n\n $select = $subject->getConnection()->select();\n\n $select->from(\n $subject->getResource()->getTable('catalog_category_product'),\n ['product_id', 'category_id']\n );\n $select->where('product_id IN (?)', $ids);\n\n $data = $subject->getConnection()->fetchAll($select);\n\n $categoryIds = [];\n foreach ($data as $info) {\n if (isset($categoryIds[$info['product_id']])) {\n $categoryIds[$info['product_id']][] = $info['category_id'];\n } else {\n $categoryIds[$info['product_id']] = [$info['category_id']];\n }\n }\n\n foreach ($subject->getItems() as $item) {\n $productId = $item->getId();\n if (isset($categoryIds[$productId])) {\n $item->setCategoryIds($categoryIds[$productId]);\n } else {\n $item->setCategoryIds([]);\n }\n }\n\n $subject->setFlag('category_ids_added', true);\n return $result;\n }\n}<\/pre>\n\n\n\n