Yes, you can, but not as easily as in Excel. Some techniques that might help are in this webinar: http://www.datawatch.com/video/invisible-data-advanced-techniques-for-datawatch-modeler/
Do you want to compare row(N) always with row(N-1)? What do you do with Row 1? Or if you want to compare Row(N) with Row(N+1), what do you do with the last row?
Essentially, the easiest technique is to get the filtered and sorted data into a table, add two calculated fields (Rowno() and Rowno()+1) export it as an Access MDB file, then make an
external lookup to this, joining Rowno() with Rowno()+1 or vice versa.
But assume you'll get a null lookup at either the top or the bottom of your data (just like you would in Excel, BTW).
Ah, my good friend Olly. Long time no see. Thanks for the response. It would be Row(N) with Row(N-1), starting at Row(2) with null values in the first row; data sorted by patient number then admit date. I'm trying to track readmissions by comparing the discharge date of Row(N) with the admit date of Row(N-1). I'll have a look at the webinar and see where it takes me.