I am looking to build a report that needs to highlight if a customer has drifted spending on an item.

 

Each item sold has a date stamp and qty. What I want to try and do is highlight where an customer has stopped buying an item for example. Item purchased months 12,11,10,9,8,7,6,5,4 but not in 3,2 or 1

 

Or where sales are increasing for example Qty of item > in period 2 than period 1 (P1 M12,11,10 - P2 M10,9,8,7) or Qty of item > in period 4 than 3 etc.....

 

We have up to 5000 items and 18,000 customers in the table.

 

Ideally I would like to display the items a customer is growing sales on and dropping sales on with an Green UP or Red DOWN arrow to help the user see quickly and easily.

 

Any ideas on who to tackle this would be greatly appreciated.