select
    td.dept_code,
    td.dept_name,
    to.order_no,
    tc.cust_code,
    tc.cust_name,
    to.order_amt
from TBL_ORDERS as to
inner join TBL_DEPT as td on td.dept_code = to.dept_code
left outer join TBL_CUST as tc on tc.cust_code = to.cust_code
order by 
    to.dept_code asc,
    to.order_no asc
;