Work out date difference when there is only one date I have 2 records, one details when the stop clock was stopped and the other started.  I only have the one date value in each record.  I'm trying to work out the difference between the stop and start dates.  I'm looking for pointers.  I thought by doing something like:

SELECT e1.ID, MIN(e1.EventTime) AS [StopTotalMinutes]
          ,MAX(e2.EventTime) AS [StartTotalMinutes]
  FROM event AS e1
  JOIN event AS e2
    ON e1.ID = e2.ID


I would have been able to work something out, but I'm failing.

So, Table and some sample data is:

ID    |    EventTime     |   Action
1       2012-01-01 10:00      Stop
1       2012-01-01 13:31     Start
1       2012-01-03 09:45      Stop
2       2012-01-01 11:12      Stop
2       2012-01-10 15:35     Start
2       2012-01-11 08:39      Stop
This should do it:

SELECT e1.ID, DATEDIFF(MINUTE,e1.EventTime,e2.EventTime) [Minutes]
FROM (SELECT * FROM event WHERE Action = 'Start') AS e1
LEFT JOIN (SELECT * FROM event WHERE Action = 'Stop') AS e2
ON e1.ID = e2.ID