The Month field does not exist in the Orders table and needs to be incorporated in the table using he Calendar table.

In the Orders table, some CustomerlD values are null because there are orders with no customer.

and needs to be incorporated in the table using the Calendar table, null because there are orders with no customer

In the Orders table, some values in the CustomerlD field do not exist in the Customers table.

The OrderDate field values in the Calendar table do not match with the values in the OrderDate field from the Orders table