I have a table that contains the following:

    DataDate                 Value
    2010-03-01 08:31:32.000  100
    2010-03-01 08:31:40.000  110
    2010-03-01 08:31:42.000  95
    2010-03-01 08:31:45.000  101
    .                        .
    .                        .
    .                        .

I need to multiply the value column by the difference in time between the current and previous rows and sum that for the entire day.

I currently have the data set up to come in every 10 seconds which makes for a simple conversion in the query:

    SELECT Sum((Value/6) FROM History WHERE DataDate BETWEEN @startDate and @endDate

Where @startDate and @endDate are today&#39;s date at 00:00:00 and 11:59:59.

Before I set the data to be collected every 10 seconds it was collected whenever the Value changed.  There aren&#39;t any duplicate entries in terms of time, the minimum time difference is 1 second.  

How can I set up a query to get the elapsed time between rows for the case when I don&#39;t know the time interval between readings?

I am using SQL Server 2005.

All Difference Between-Rows Solutions on Gang of Coders

Total of 1 Difference Between-Rows Solutions

Calculate Time Difference Between Two Rows