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 JOIN TBL_CUST AS CUST ON ORDERS.CUST_CODE = CUST.CUST_CODE
ORDER BY DEPT.DEPT_CODE, ORDERS.ORDER_NO;