ALTER PROCEDURE dbo.groupby_bar_categories_products_received 

AS
SELECT  
Category.product_category_id,   
Category.product_category_name as [Category],
SUM(DeliveryItems.product_stock_received) as [Stock Received],
SUM(DeliveryItems.product_cost_price * product_stock_received) as [Stock Cost]
                      
FROM        
bar_products_delivery_items DeliveryItems
INNER JOIN bar_products Products ON Products.product_id = DeliveryItems.product_id
INNER JOIN bar_products_category Category ON Category.product_category_id = Products.product_category_id  

group by 
Category.product_category_id,
Category.product_category_name