select
    td.DEPT_CODE,
    td.DEPT_NAME,
    TBL_ORDERS.ORDER_NO,
    tc.CUST_CODE,
    tc.CUST_NAME,
    TBL_ORDERS.ORDER_AMT
from
    TBL_ORDERS 
left join
    TBL_CUST as tc on tc.CUST_CODE = TBL_ORDERS.CUST_CODE
inner join
    TBL_DEPT as td on td.DEPT_CODE = TBL_ORDERS.DEPT_CODE
order by
    td.DEPT_CODE asc,
    TBL_ORDERS.ORDER_NO asc
;