Pilih baris di mana nilai kolom telah berubah

Saya pikir ini yang Anda cari:

;WITH x AS
(
  SELECT value, time, rn = ROW_NUMBER() OVER 
  (PARTITION BY Value ORDER BY Time)
  FROM dbo.table
)
SELECT * FROM x WHERE rn = 1;

Ini mungkin lambat jika resultet besar dan tidak ada indeks pendukung yang baik...

EDIT

Ah, tunggu sebentar, nilainya naik dan turun, tidak hanya naik... jika demikian, Anda dapat mencoba pendekatan yang jauh lebih lambat ini:

DECLARE @x TABLE(value INT, [time] DATETIME)

INSERT @x VALUES
(0,'20120615 8:03:43 PM'),--
(1,'20120615 8:03:43 PM'),--*
(1,'20120615 8:03:48 PM'),--
(1,'20120615 8:03:53 PM'),--
(1,'20120615 8:03:58 PM'),--
(2,'20120615 8:04:03 PM'),--*
(2,'20120615 8:04:08 PM'),--
(3,'20120615 8:04:13 PM'),--*
(3,'20120615 8:04:18 PM'),--
(3,'20120615 8:04:23 PM'),--
(2,'20120615 8:04:28 PM'),--*
(2,'20120615 8:04:33 PM');

;WITH x AS
(
  SELECT *, rn = ROW_NUMBER() OVER (ORDER BY time)
  FROM @x
)
SELECT x.value, x.[time]
FROM x LEFT OUTER JOIN x AS y
ON x.rn = y.rn + 1
AND x.value <> y.value
WHERE y.value IS NOT NULL;

Hasil:

value  time
-----  -----------------------
1      2012-06-15 20:03:43.000
2      2012-06-15 20:04:03.000
3      2012-06-15 20:04:13.000
2      2012-06-15 20:04:28.000