SELECT D.DEPT_CODE,D.DEPT_NAME,O.ORDER_NO,C.CUST_CODE,C.CUST_NAME,O.ORDER_AMT
FROM TBL_ORDERS O
INNER JOIN TBL_DEPT D ON D.DEPT_CODE = O.DEPT_CODE
LEFT JOIN TBL_CUST C ON C.CUST_CODE = O.CUST_CODE
ORDER BY D.DEPT_CODE , O.ORDER_NO;