Key-Based Sheet Merge
Join two or more CSV files on a shared key column — like a VLOOKUP or database join — combining their fields into a single row per match.
How to use Key-Based Sheet Merge
- Start by providing the required input: Drop 2 or more CSV files to join.
- Set the inputs and options shown here: Key column in "${FT.escapeHtml(p.name)}".
- Run the tool with Join Files.
- Review the results, then choose an output control: Download Joined CSV.
A VLOOKUP-style join without opening a spreadsheet formula bar
Combining data from two or more CSVs that share a common key column — a customer ID across an orders file and a contacts file — is exactly what VLOOKUP or a database join does, but setting that up in a spreadsheet for more than two files gets unwieldy fast. Selecting a key column per file and joining directly handles it in one step regardless of how many files are involved.
What happens when a key doesn't match in every file
Rows from the base (first) file are always kept, with matching data pulled in from the other files wherever the key exists there — if a key is missing from a secondary file, those columns are simply left blank for that row rather than dropping the row entirely.
Which file determines the base row set?
The first file you add — every row in the output corresponds to a row in that file, with other files' data joined in alongside it.
Can key columns have different names across files?
Yes — you select the key column independently for each file, so they don't need matching names, only matching values.
Just need to stack rows without joining on a key?
Use Data Combiner or Multi-Sheet Merger instead for row-stacking without a key-based join.