(
    [rowid] [int] primary key IDENTITY(1,1) NOT NULL,
    [name] [nchar](10) NULL,
    [price] [int] NULL
)
insert INTO Products VALUES('蘋果',    50);
insert INTO Products VALUES('橘子',    100);
insert INTO Products VALUES('橘子',    100);
insert INTO Products VALUES('橘子',    100);
insert INTO Products VALUES('香蕉',    80);
insert INTO Products VALUES('香蕉',    80);

where p1.rowid<
(
    select MAX(p2.rowid) from products p2 
    where p1.name=p2.name and p1.price=p2.price
)
--結(jié)果：
--    rowid        name    price
--      1            蘋果        50
--      4            橘子        100
--      6            香蕉        80