create table CustomerOrder (
 CustomerID int,
 OrderID int
);

insert into CustomerOrder (CustomerID, OrderID)
values (1,1),
(1,2),
(2,3),
(3,4),
(1,5),
(3,6),
(2,7),
(2,8),
(2,9),
(3,10),
(1,11),
(1,12),
(2,13),
(3,14),
(2,15);