The following will return all orders ...
SELECT * FROM members, orders
WHERE orders.memberid = members.id
ORDER BY members.company
The following will return a particular order (id=1) ...
SELECT * FROM members, orders
WHERE orders.memberid = members.id
AND orders.id = 1
ORDER BY members.company
The following will return all orders for a particular member (id=1) ...
SELECT * FROM members, orders
WHERE orders.memberid = members.id
AND members.id = 1
ORDER BY members.company