SELECT b.DEPT_CODE AS DEPT_CODE ,  a.DEPT_NAME
FROM TBL_ORDERS AS b
FULL OUTER JOIN TBL_DEPT AS a
ON a.DEPT_CODE = b.DEPT_CODE
UNION
SELECT c.DEPT_CODE as DEPT_CODE ,  a.DEPT_NAME
FROM TBL_SALES AS c 
FULL  OUTER JOIN TBL_DEPT AS a
ON a.DEPT_CODE = c.DEPT_CODE
ORDER BY DEPT_CODE ASC