Ihenen ton

Using the UNHON operator, in one list return all customers who do net have an imoice and all products that were not salel.

For each customer without an invoice, return:

the string customer

the customer id

the customer$\_$name

For each product without an invoice, return:

the string product

$2$

the product id

the product$\_$name

$3$

The columns must be in the order shown, but row order does not matte

Table definitions and a data sample are given below.