Creo que esto es lo que buscas:
;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;
Esto puede ser lento si el conjunto de resultados es grande y no hay un buen índice de apoyo...
EDITAR
Ah, espera un segundo, los valores suben y bajan, no solo hacia arriba... si ese es el caso, puedes intentar este enfoque mucho más lento:
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;
Resultados:
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
