select dept.DEPT_CODE,dept.DEPT_NAME,orders.ORDER_NO,cust.CUST_CODE,cust.CUST_NAME,orders.ORDER_AMT
from TBL_ORDERS as orders 
inner join TBL_DEPT as dept on orders.DEPT_CODE = dept.DEPT_CODE
left outer join TBL_CUST as cust on cust.CUST_CODE = orders.CUST_CODE 
order by dept.DEPT_CODE ASC,orders.ORDER_NO ASC;