SELECT
    td.DEPT_CODE,
    DEPT_NAME,
    ORDER_NO,
    tc.CUST_CODE,
    CUST_NAME,
    ORDER_AMT
FROM
    TBL_ORDERS as tos
LEFT JOIN
    TBL_CUST as tc
ON
    tos.CUST_CODE = tc.CUST_CODE
INNER JOIN
    TBL_DEPT as td
ON
    tos.DEPT_CODE = td.DEPT_CODE
ORDER BY
    td.DEPT_CODE ASC, tos.ORDER_NO ASC;