Question

In SQL Server 2008,

I have a table for tracking the status history of actions (STATUS_HISTORY) that has three columns ([ACTION_ID],[STATUS],[STATUS_DATE]).

Each ACTION_ID can have a variable number of statuses and status dates.

I need to convert these rows into columns that preferably look something like this:

[ACTION_ID], [STATUS_1], [STATUS_2], [STATUS_3], [DATE_1], [DATE_2], [DATE_3]

Where the total number of status columns and date columns is unknown, and – of course – DATE_1 correlates to STATUS_1, etc. And I’d like for the status to be in chronological order (STATUS_1 has the earliest date, etc.)

My reason for doing this is so I can put the 10 most recent Statuses on a report in an Access ADP, along with other information for each action. Using a subreport with each status in a new row would cause the report to be far too large.

Is there a way to do this using PIVOT? I don’t want to use the date or the status as a column heading.

Is it possible at all?

I have no idea where to even begin. It’s making my head hurt.

Answer 1

Let us suppose for brevity that you only want 3 most recent statuses for each action_id (like in your example).

Then this query using CTE should do the job:

WITH rownrs AS
(
 SELECT
   action_id
  ,status
  ,status_date
  ,ROW_NUMBER() OVER (PARTITION BY action_id ORDER BY status_date DESC) AS rownr
 FROM
  status_history
)

SELECT
  s1.action_id AS action_id

 ,s1.status AS status_1
 ,s2.status AS status_2
 ,s3.status AS status_3

 ,s1.status_date AS date_1
 ,s2.status_date AS date_2
 ,s3.status_date AS date_3

FROM

(SELECT * FROM rownrs WHERE rownr=1) AS s1

 LEFT JOIN
(SELECT * FROM rownrs WHERE rownr=2) AS s2
 ON s1.action_id = s2.action_id

 LEFT JOIN
(SELECT * FROM rownrs WHERE rownr=3) AS s3
 ON s1.action_id = s3.action_id

NULL values will appear in the rows where the action_id has less then 3 status-es.