rowlane

Home / Tools / Join tables by key

Combine · Browser based

Join tables by key

Join two tables by selected unique key columns. Choose inner, left, or full output and review unmatched records without creating Cartesian duplicates.

Fictional sample loaded for demonstration. Your file is not sent to a Rowlane server.

1. Bring in a table

CSV or TSV · UTF-8 text · up to 5 MiB, 20,000 records, and 100 columns

All values stay text, including IDs like 0017.
Quoted commas, quotes, and line breaks are preserved. Choose the delimiter if detection is wrong.
Both starter tables are fictional. Review their headers and keys before running.
Match unique keys

Loading table…

What this tool does

Each input needs unique, nonblank keys for matching. Duplicate nonblank keys stop the join. The second key field is represented by the first key column in the output; same-named non-key columns receive a “(second)” suffix.

How to use it

  1. Load both tables and select the key field in each.
  2. Choose inner, left, or full join depending on which unmatched records you need to keep.
  3. Run the join and inspect matched, unmatched, and suffixed columns before export.

2. Check the input

Confirm the header and a few records before applying a rule.

Questions

What to expect

What does the second suffix mean?

When a non-key header already exists in the first table, the second table’s field is renamed with “(second)” and a numeric suffix if needed.

Are unmatched records dropped?

Inner drops them, left keeps unmatched first-table rows, and full keeps unmatched rows from both tables.

Review the destination rules. A valid CSV or a clean report does not guarantee that another system will accept the file. Keep your original and verify any export before importing it.