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