DATA / TOOL 14
CSV key join
Match two tables by a key and keep all left-table rows.
Browser-local · No upload · Free
Your workspace
Your result
LOCAL ONLYReady when you are.
A small step from input to done.
Your result will appear here.A QUICK WALKTHROUGH
How to use it
- Paste two CSVs sharing a key column
- enter the key name and run the left join.
TRY THIS EXAMPLE
A result you can check.
Left IDs 1 and 2 joined to right IDs 1 and 3 produce Ada,Designer and Sam with an empty Role. Right-only ID 3 is omitted.
Select Load example, then Run tool. Sample files are generated locally.
What to know
Keys are exact strings. Duplicate right-side keys are rejected to avoid silently multiplying rows. Overlapping columns receive a right_ prefix.
Keep an original copy. Review the output before sharing or relying on it. Reset clears this workspace; inputs are not saved by Handyfold.