What makes a useful SKU key?
A useful key is stable, present in both files and unique for one sellable item. Supplier item numbers often work better than descriptions, barcodes copied through spreadsheets or internal row numbers.
Protect leading zeros
Identifiers such as 000451 are text, even when they contain only digits. Import and format them as text in both files. If one file stores the value as 451, an exact match will fail or connect the wrong data after manual conversion.
Normalize carefully
Trimming accidental spaces is usually safe. Changing case may be safe if the supplier treats upper- and lower-case SKUs as identical. Removing punctuation or internal spaces is riskier because it can merge genuinely different identifiers. Keep the original value available for review.
Find duplicates before matching
A duplicate SKU can represent repeated rows, different pack sizes or a data error. Do not silently keep the first match. Count occurrences in each file and resolve duplicates or document how they should be aggregated.
Understand missing matches
- Only in the new file: usually a new item.
- Only in the old file: usually a removed item.
- Blank SKU: invalid for key-based matching.
- Changed SKU: cannot be inferred as the same product without an additional mapping.
Composite keys
Some lists require a combination such as supplier SKU plus pack size. The current WoluTools comparison selects one SKU column and does not claim automatic composite-key matching. Prepare a combined key before upload if that is required, and verify that it is unique.
Inspect a complete match result
The example separates matched price changes from new and removed SKUs.
View example files