CREATE TABLE winsales(
salesid int,
dateid date,
sellerid int,
buyerid text,
qty int,
qty_shipped int);
INSERT INTO winsales VALUES
(30001, '8/2/2003', 3, 'b', 10, 10),
(10001, '12/24/2003', 1, 'c', 10, 10),
(10005, '12/24/2003', 1, 'a', 30, null),
(40001, '1/9/2004', 4, 'a', 40, null),
(10006, '1/18/2004', 1, 'c', 10, null),
(20001, '2/12/2004', 2, 'b', 20, 20),
(40005, '2/12/2004', 4, 'a', 10, 10),
(20002, '2/16/2004', 2, 'c', 20, 20),
(30003, '4/18/2004', 3, 'b', 15, null),
(30004, '4/18/2004', 3, 'b', 20, null),
(30007, '9/7/2004', 3, 'c', 30, null);