Updating Inventory After Inner Join

I have this script which pulls in all products from a product inventory with a sku range starting in 9 and ending in BK

select Product.ProductID,Product.Name,Product.SKU,ProductVariant.Inventory
From Product
Inner join ProductVariant
on Product.ProductID=ProductVariant.ProductID
where Product.SKU like '9%BK'

If I wanted to add something to this script where the inventory for all those products in the results above was changed from 0 to 20 how would I add this? Just changing those who had a a SKU starting with 9 and ending in BK