I have some Excel files with a few million records between them, and they are grouped by source filename. I would like to write a VBA macro that places the source filename of each record in the first column so they will be easy to trace when I combine them into a database.
I am assuming the best way to do this is to use autofill coding on some sort of loop but I'm having trouble with the autofill part. The files are laid out exactly like in the exampleData tab in the attached file and I would like it to look like the solution tab. Thanks!