SELECT
    TD.DEPT_CODE AS DEPT_CODE,
    TD.DEPT_NAME AS DEPT_NAME,
    ORDER_NO,
    TC.CUST_CODE AS CUST_CODE,
    TC.CUST_NAME AS CUST_NAME,
    ORDER_AMT
FROM
    TBL_ORDERS AS TOR
INNER JOIN TBL_DEPT AS TD
    ON TOR.DEPT_CODE = TD.DEPT_CODE
LEFT JOIN TBL_CUST AS TC
    ON TOR.CUST_CODE = TC.CUST_CODE
ORDER BY
DEPT_CODE, ORDER_NO;