SELECT dep.DEPT_CODE, DEPT_NAME, ORDER_NO, cus.CUST_CODE, CUST_NAME, ORDER_AMT
FROM TBL_ORDERS ord INNER JOIN TBL_DEPT dep
    ON ord.DEPT_CODE=dep.DEPT_CODE
LEFT OUTER JOIN TBL_CUST cus
    ON ord.CUST_CODE=cus.CUST_CODE
ORDER BY dep.DEPT_CODE, ORDER_NO