[cflsystems]

The query won't work the way it is.

This

UPDATE xcart_products, xcart_products_lng_en SET xcart_products.title_tag = xcart_products_lng_en.product, xcart_products.meta_keywords = xcart_products_lng_en.product, xcart_products.meta_description = xcart_products_lng_en.product WHERE xcart_products.productid = xcart_products_lng_en.productid;

But make sure you backup first