Error Trigger Database& show data to frontend

I have a problem with triggers not working on PhpMyAdmin, I have created a database trigger based on metadata and it has been inputted correctly, but when making a product purchase it is not updated automatically. My goal is to display on the frontend when purchasing by accumulating based on the stock owned by the audience.

I need a freelancer who understands SQL, woocommerce, WordPress, and who can work with me right away to finish as soon as possible.