You have WordPress web store and you use Woocommerce as a solution. Now, you might have variable products or just simple products but you have a need to place exact the same SKU on different products. And you get the error notice:
”Variation SKU must be unique”
“Invalid or duplicated Sku”.
Here is the WP plugin we made as a simple solution. Just download zipped file, unzipp it on your computer. Then upload the plugin file in wp-content/plugins/ directory on your server, go to WP admin and activated the plugin. Voila. Now you can add same SKU on different products, and woocommerce will accept it.