Adding/Subtracting across adjacent table rows

[w1dge]

Is it possible to perform calculations across 2 adjacent rows in SQL?

At the moment, I have a running count that tracks the number of updates that go into our database against a specific JobID.

Is it possible to subtract the running count for a previous update from the current update.

For example, I would like my resulting table to end up looking like this

JobID Time Updates Since Last Update
1 10:10:00 1 1
1 10:30:45 3 2
1 11:15:10 9 6


In this example, the Since Last Updates should be found by
subtracting the Updates at 10:10:00 from the Updates at 10:30:45 giving 2 and the Updates at 10:30:45 from 11:15:10 giving 6. It would continue like this for as many rows of data have the same JobID (which could be several hundred!)

What I would then like to do is use the 'Since Last Update' number to display only those updates that are applicable to a certain Time, perhaps using Select Top in SQL.

Am I approaching this from the right direction, or would it perhaps be better to try to do this using Time, as this will always be unique?


Thanks for looking

W1dge

 

[Pat Hartman]

Data stored in one table row should not be dependent upon data from another row. Calculate the differences in a report.