How it's possible join into one query:
UPDATE products SET products_price='50.0000' where products_id in (SELECT products_id FROM products_description where products_name='Dual 111 HDMI mit USB') LIMIT 1;
UPDATE products SET products_price='36.4900' where products_id in (SELECT products_id FROM products_description where products_name='HYUNDAI 5003') LIMIT 1;