Thanks for the guidance GSquared!

I learned a lot about CTE's, the row_number function and joins.

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WITH myCTE AS

(select database_id

,file_id,capture_time

,row_number () over (order by database_id,file_id,capture_time) as 'RowNumber'

,num_of_writes

,io_stall_write_ms

FROM pcpt1)

SELECT

myCTE.database_id

,myCTE.file_id

,myCTE.capture_time

,myCTE.num_of_writes

,myCTE.num_of_writes-pcpt1.num_of_writes as 'Writes'

,myCTE.io_stall_write_ms-pcpt1.io_stall_write_ms...