SELECT
  orders.DEPT_CODE,
  DEPT_NAME,
  ORDER_NO,
  cust.CUST_CODE,
  CUST_NAME,
  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 orders.CUST_CODE = cust.CUST_CODE
ORDER BY
  orders.DEPT_CODE asc,
  orders.ORDER_NO asc;