$1.$ Show all columns from all $4$ tables, include all records from each table in the result.

$2.$ Write a SQL query to show a table with columns Product Class, Product Line, and Color that shows all the different combinations of Product Class, Product Line and Product Color.

$3.$ Write a SQL query to show a table with columns Customer ID and Product ID of only products ordered by the customer and meets the following requirements:

a$.$ Customer ID should be included for all customers.

b$.$ Product ID included are only for products ordered by the customer with Customer ID in the first column.

c$.$ If the same customer has purchased the same product multiple times, the pair of Customer ID and Product ID should not be repeated.

Additional Notes:

$-$ Customer ID is used to uniquely identify each customer and is available as CustomerID in SALES$\_$ORDERS table as well as CustID in CUSTOMER table.

$-$ Product ID is used to uniquely identify each product and is available as ProductID in both PRODUCT and ORDER$\_$DETAILS tables.

$4.$ Write a SQL query to show a table with columns Product ID and Customer ID$,$ and meets the following requirements:

a$.$ Customer ID should be included only for all customers who have ordered that product.

b$.$ Product ID for all products should be included.

c$.$ If the same product has been ordered by the same customer multiple times, the pair of Product ID and Customer ID should not be repeated.

d$.$ The columns should be named $$Product ID Ordered$,$ and $$Ordered by Customer ID$$

Additional Notes:

$-$ Product ID is used to uniquely identify each product and is available as ProductID in both PRODUCT and ORDER$\_$DETAILS tables.

$-$ Customer ID is used to uniquely identify each customer and is available as CustomerID in SALES$\_$ORDERS table as well as CustID in CUSTOMER table.