Get parent SKU (configurable or bundle) from child SKU Magento 2

Question

On the order page(backend) I need to be able to obtain the parent SKU using a child SKU.

I've tried several code snipped from both the Magento forums and similar questions here on StackOverflow without success.

I'm able to determine if a product is just a simple product without a parent by using getTypeId() but after that everything I try fails to result in getting at the parent SKU.

Magento 2.2.6

Answer 1

Configurable, bundle and grouped are all different and require different means to get their parents. The methods are listed within the relevant files.

Magento\ConfigurableProduct\Model\Product\Type\Configurable.php

/** 
* Retrieve configurable parent ids array by required child
*
* @param  int|array $childId
* @return array
*/
public function getParentIdsByChild($childId)
{
   return $this->_catalogProductTypeConfigurable->getParentIdsByChild($childId);
} 

Magento\Bundle\Model\Product\Type.php

/**
* Retrieve bundle parent ids array by required child
*
* @param int|array $childId
* @return array
*/
public function getParentIdsByChild($childId)
{
   return $this->_bundleSelection->getParentIdsByChild($childId);
}

Magento\GroupedProduct\Model\Product\Type\Grouped.php

/**
* Retrieve grouped parent ids array by requested child
*
* @param int|array $childId
* @return array
*/
public function getParentIdsByChild($childId)
{
   return $this->productLinks->getParentIdsByChild(
       $childId,
       \Magento\GroupedProduct\Model\ResourceModel\Product\Link::LINK_TYPE_GROUPED
  );
}

Lastly, in case you need to quickly get the sku from mysql .

#Select parent of a sku
 SELECT
  parent.sku
FROM
  catalog_product_entity parent
WHERE parent.row_id =
  (SELECT
    relationship.parent_id
  FROM
    catalog_product_super_link relationship
  WHERE relationship.product_id =
    (SELECT
      child.entity_id
    FROM
      catalog_product_entity child
    WHERE child.sku = "SKU")
  );