title: subtract two columns from different tables and update the inventory
body: <p>I need to update the product quantity in store inventory table based on quantity sold in SALELINE table</p>
  
  <p>so, I want to subtract QTYONHAND from Store_inv and QTYSOLD from SALELINE table for each product which has a Product_id</p>
  
  <p>Store_inv and SALELINE both has a Product_id as (FK)</p>