Private CSV join workbench
Join two CSV tables by key.
Choose the left and right tables, key columns and join type, then review the joined result and unmatched rows before saving.
Choose two CSV files
Rows to keep, such as orders
Values to add, such as a product master
Only settings are loaded; rows and filenames are never included.
Key columns
Choose the same number of corresponding columns on both sides.
LeftRight
Join and comparison
Right columns to add
Choose both CSV files.
Review join result
| Left row | Right row | Status |
|---|
Save
Only the reviewed current result is saved. Source files are never changed.
Input, filenames, keys and results stay in memory and are never sent outside this browser.
Safe join boundaries
- Duplicate right-side keys stop the join; no arbitrary row is selected.
- Empty keys never match and are visible as unmatched in a left outer join.
- Column collisions get a visible
right_prefix; left values are not overwritten.