View grouped records in a date or time sequence. P

Say you had a table in your SQL Server (EDIT: prensently SQL Server 2008) database that look like this:

Date                    Id State
=================================
2013-09-12 15:02:41,844 1 OK
2013-09-12 15:02:41,844 2 OK
2013-09-12 15:02:41,844 3 ERROR
2013-09-12 15:02:41,844 4 ERROR
2013-09-12 15:02:41,844 5 ERROR
2013-09-13 15:02:41,844 1 ERROR
2013-09-14 15:02:41,844 1 OK
2013-09-15 15:02:41,844 1 ERROR
2013-09-15 15:02:41,844 2 ERROR

The purpouse of the table is to save records state. I wrote this table but now i cannot figure out how to query it for an overview of the different states during a time sequence.

The result i am looking for is this:

2013-09-12 16:00:00 OK 2
2013-09-12 16:00:00 ERROR 3
2013-09-13 16:00:00 OK 1
2013-09-13 16:00:00 ERROR 4
2013-09-14 16:00:00 OK 2
2013-09-14 16:00:00 ERROR 3
2013-09-15 16:00:00 OK 0
2013-09-15 16:00:00 ERROR 5

EDIT: What i am trying to achieve is a day-by-day view of the state of my objects. which objects has an error and which ones are ok. Maybe a garage would be a better example, but i will stick to this.

On the 12th 3 objects had ERROR and 2 where OK.
On the 13th one object went from OK to Error. I now have 4 objects in a ERROR state and one that is OK.
On the 14th my object with id 1 is fixed and i am now back to two objects that are OK >and three that has an ERROR state

I have figured out (found) how to generate a sequence of dates (without using variable declarations) like this:

;WITH dates
AS (
    SELECT CAST('2013-12-17 16:00:00' AS DATETIME) 'date'

    UNION ALL

    SELECT DATEADD(dd, 1, t.DATE)
    FROM dates t
    WHERE DATEADD(dd, 1, t.DATE) <= GETDATE()
    )
SELECT dates.DATE   
FROM dates

And i have a query that does the relevant grouping (i think) that delivers a desired output (and point):

Date State Count(state)
=======================    
2013-09-12 16:00:00 OK 2
        2013-09-12 16:00:00 ERROR 3
        2013-09-13 16:00:00 ERROR 1
        2013-09-14 16:00:00 OK 1
        2013-09-15 16:00:00 ERROR 1

So the question is, how do you marry the sequence of dates to my grouping result to achieve the desired result.

With SQL Server 2012 providing window functions you can use the following query:

SELECT date,
       sum(ok_mod) over (order by date) as ok
FROM (
  SELECT date,
         sum(case when state = 'OK' then 1
                  when state = 'ERROR' and prev_state is not null then -1
                  else 0
             end) as ok_mod
  FROM (
    SELECT date, id, state,
           lag(state) over (partition by id order by date) prev_state
    FROM data
  ) AS data
  GROUP BY date
) AS data
ORDER BY date;

This gives you only OK part, but you can easily union corresponding query for ERROR part also. SQL Fiddle here.

With 2008 version imho you won't make it without a procedure or really complex query.