I have managed to work a PS Script that added circa 9k items from a CSV file. After working some parsing issues with date/time, People fields etc. It's finally worked and all 9k items now sit on the SharePoint list, yaay.
I've just been approached, asking "can you fit in another column" with another 9k list-items, only this time it's just one column that needs adding/updating on the same list I just imported.
The concept that I can't understand is, I want to update the already created items, and not all of them either, just specific ones that fall within a range. What can I use as the anchor / unique identifier? I'm thinking item ID. What logic do I use to tell is to only update the ones that match the same ID number that's in the CSV file?