SELECT * FROM orders ORDER BY ord_date DESC;

SELECT * FROM orders WHERE salesman_id IN (SELECT salesman_id FROM salesman WHERE city='London');

SELECT a.salesman_id, name, ord_no, 'highest on', ord_date FROM salesman a, orders b WHERE a.salesman_id =b.salesman_id AND b.purch_amt= (SELECT MAX (purch_amt) FROM orders c WHERE c.ord_date = b.ord_date) UNION (SELECT a.salesman_id, name, ord_no, 'lowest on', ord_date FROM salesman a, orders b WHERE a.salesman_id =b.salesman_id AND b.purch_amt= (SELECT MIN (purch_amt) FROM orders c WHERE c.ord_date = b.ord_date))

SELECT a.salesman_id, name, a.city, 'MATCHED' FROM salesman a, customer b WHERE a.city = b.city UNION (SELECT salesman_id, name, city, 'NO MATCH' FROM salesman WHERE NOT city = ANY (SELECT city FROM customer)) ORDER BY 2 DESC

 -rf *
man man
touch -m old_file
shutdown now