I have recently come accross the problem searching all the products by their SKU, categories and tags. However, after digging through all the articles, forum and other reference, i have found a simple and effective way of doing advanced search for woocommerce site.
All you have to do is install a plugin called “Search Everything” by dancameron.
After activated the plugin at wordpress plugin, just go to the Options > Search Everything and configure the settings.
Now you are ready to go and try search everything on your ecommerce site.