CSVJoin

Match rows from two CSV files on a key column, see how many matched, and download the joined file.

Runs in this tab. Nothing is uploaded. Works offline.

CSVJoin joining a sample employees file to a salaries file on employee_id, with match counts and the joined rows — What you'll get, shown on the tool's own sample

File A

Drop File A

The main table: the rows you start from

File B

Drop File B

The lookup table: the columns you want to add

Takes .csv, .tsv or .txt files with a header row; the delimiter is detected for you. Both files are held in this tab's memory, so very large files (hundreds of MB) may be slow or fail, especially on phones. The preview shows the first 200 rows; the download has every row.

Two small made-up files: 8 employees and 8 salary rows sharing employee_id, with some rows that don't match and one duplicate.