SELECT
 TD.DEPT_CODE AS DEPT_CODE,
 TD.DEPT_NAME AS DEPT_NAME,
 T.ORDER_NO AS ORDER_NO,
 TC.CUST_CODE AS CUST_CODE,
 TC.CUST_NAME AS CUST_NAME,
 T.ORDER_AMT AS ORDER_AMT
FROM
 TBL_ORDERS AS T
INNER JOIN
 TBL_DEPT AS TD ON TD.DEPT_CODE = T.DEPT_CODE
LEFT JOIN
 TBL_CUST AS TC ON TC.CUST_CODE = T.CUST_CODE
WHERE
 TD.DEPT_CODE IS NOT NULL
ORDER BY TD.DEPT_CODE ASC, T.ORDER_NO ASC;