CASE use for NULL values ordered last

in this way ‘0’ representing the known values ​​are ranked first, ‘1’ representing the NULL values ​​are sorted by the last:

SELECT ID
      ,REGION
      ,CITY
      ,DEPARTMENT
      ,EMPLOYEES_NUMBER
  FROM DEPT
  ORDER BY 
  CASE WHEN REGION IS NULL THEN 1 
  ELSE 0
  END, 
  REGION

ID | REGION |CITY |DEPARTMENT|EMPLOYEES_NUMBER|
—— | —— |—— |—— |—— |
10 | Mid-Atlantic |Philadelphia |RESEARCH |13|
14 | Mid-Atlantic |New York |SALES |12 |
9 | Midwest |Chicago |SALES |8 |
12 | New England |Boston |MARKETING |9|
5 | West |Los Angeles |RESEARCH |11 |
15 | NULL |San Francisco |MARKETING |12|
4 | NULL |Chicago |INNOVATION |11 |
2 | NULL |Detroit |HUMAN RESOURCES |9|