How to merge two excel workbooks with a left or inner join on a key column
- Step 1Drop two Excel files — Upload File A (left) and File B (right) — the files to be joined.
- Step 2Configure join keys — Enter the column name in each file that contains the shared key (e.g. 'Customer ID').
- Step 3Download the joined file — The merged workbook is ready. Metrics show how many rows were matched.
Frequently asked questions
What happens to columns with the same name in both files?+
The right file's key column is dropped to avoid duplication. Other same-named columns from the right file are included with their original name — rename them in the Header Sanitizer if needed.
Does it support joining on multiple key columns?+
Single key column join only in this version. Composite-key joining is on the Pro roadmap.
What is the difference between left join and inner join?+
Left join keeps all rows from File A, with NULL values where File B has no match. Inner join only keeps rows where both files have matching key values.
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