select all column with one column in reverse order???

CREATE TABLE [dbo].[gupta](
    [a] [int] NULL,
    [b] [int] NULL,
    [c] [int] NULL
) ON [PRIMARY]


INSERT INTO [Test].[dbo].[gupta]([a],[b],[c]) VALUES (1,2,3);
INSERT INTO [Test].[dbo].[gupta]([a],[b],[c]) VALUES (4,5,6);
INSERT INTO [Test].[dbo].[gupta]([a],[b],[c]) VALUES (7,8,9);
INSERT INTO [Test].[dbo].[gupta]([a],[b],[c]) VALUES (10,11,12);


select MAX(aX),MAX(bX), MAX(cY)
from
(
    (
      SELECT row_number() OVER (ORDER BY a ASC) n, a as aX, b as bX, -1 as cY
      FROM [Test].[dbo].[gupta]
    )
    union all
    (
       SELECT row_number() OVER (ORDER BY a DESC) n, -1 as aX, -1 as bx, c as cY
      FROM [Test].[dbo].[gupta]
    )
) as U
group by U.n;