Adds the latest CSV export to your existing spreadsheet while preserving any columns and formulas you've added. Formulas in your added columns are copied down to new rows automatically. A timestamped backup of the spreadsheet is created before any change is made.
Choose a column that uniquely identifies each response (e.g. Story ID). Existing rows with the same value get updated; new IDs get appended. Leave empty to append every CSV row as new.