Reports on customers and product categories / Who buys what and when

Reports on customers and product categories / Who buys what and when

Hello to all,

I have a great number of customers, and three categories in which I share my products. I create a report that shows me the clients that year bought the products for that month.

I need to know what my customers who have not bought all the categories of products we are selling for that month.

But I also need to see what are the customers who have not bought anything

Thanks
Felice