Scripting help to only produce a document once per row?

[Sheldon Bernstein]

Already have a spreadsheet auto-populating via template. My questions are, via batch:

1. How to load all non-empty rows from spreadsheet tab A
2. Compare column 1 in from loaded tab A to column 1 in tab B and if matched, skip that row (only want to process each row once and run a batch each night)
3. after processing is complete, update tab B with the names of those processed with a timestamp so they get skipped the following night

Hope this makes sense. Thanks for the help. Sheldon