The SQL DESC keyword specifies a descending sort order for a column within in ORDER BY clause. Values are sorted in Z to A order.
Example using DESC
The following statement sorts each Person LastName in descending order. Since noting is specified for FirstName, they are sorted in ascending order within LastName.
/* Answer */ SELECT Last, First, EmailPromotion FROM Person.Person ORDER BY Last Desc, First
Other Resources to Learn DESC
If you want to learn more about sorting and the ORDER BY clause, I would recommend reading the following articles: