SQL: Removing extra rows, based on alternating values

I have a table that has the status of a user field, and the value is either 0 or 1. Due to a coding error created several years ago, a new entry is added whether the value is actually changed or not. The table has a DateModified column for when the entry was created.

What I want to do is reduce the table down to just alternating (oscillating?) val开发者_运维技巧ues, with the earliest new value being the row that gets preserved every time. An example will make this much clearer:

What the table currently looks like:

    DateMod  Value
    6:05 pm    0
    6:01 pm    0
    5:47 pm    0
    5:33 pm    1
    5:15 pm    1
    4:07 pm    0
    3:58 pm    1
    2:23 pm    0

What the table should look like:

    DateMod   Value
    5:47 pm     0
    5:15 pm     1
    4:07 pm     0
    3:58 pm     1
    2:23 pm     0

Hopefully that makes sense. This must be possible, right?

This will work in SQL Server 2008. I used time as data type for DateMod but it is the same if you have datetime instead. Common Table Express and row_number can be used from SQL Server 2005.

-- Sample table
declare @T table(DateMod time, Value bit)
insert into @T values
    ('6:05 pm',    0),
    ('6:01 pm',    0),
    ('5:47 pm',    0),
    ('5:33 pm',    1),
    ('5:15 pm',    1),
    ('4:07 pm',    0),
    ('3:58 pm',    1),
    ('2:23 pm',    0)

-- Delete using row_number and cte    
;with cte as
(
  select *,
         row_number() over(order by DateMod) as rn
  from @T
)    
delete C2
from cte as C1
  inner join cte as C2
    on C1.rn+1 = C2.rn and
       C1.Value = C2.Value

-- Result    
select *
from @T

Result:

DateMod          Value
---------------- -----
17:47:00.0000000 0
17:15:00.0000000 1
16:07:00.0000000 0
15:58:00.0000000 1
14:23:00.0000000 0