SELECT
    OD.DEPT_CODE AS DEPT_CODE,
    DP.DEPT_NAME
FROM
    TBL_ORDERS AS OD
    LEFT OUTER JOIN TBL_DEPT AS DP ON DP.DEPT_CODE = OD.DEPT_CODE
    SELECT
    SA.DEPT_CODE AS DEPT_CODE,
    DP.DEPT_NAME
FROM
    TBL_SALES AS SA
    LEFT OUTER JOIN TBL_DEPT AS DP ON DP.DEPT_CODE = SA.DEPT_CODE

ORDER BY
    DEPT_CODE ASC;