FIELD NOTES
00123 is not 123. Keep your identifiers intact.
A product code may look like a number. Its job is to identify a record, not to take part in arithmetic.
Consider these two products:
sku,product,stock
00123,Canvas tote,4
123,Cotton pouch,2The identifiers are different text. Removing the zeros would collapse two records into one apparent SKU. Catalog Check keeps identifiers as strings and never treats these keys as the same number.
Separate the file from the app displaying it
A CSV file stores delimited text without spreadsheet cell-type metadata. A spreadsheet application may interpret a numeric-looking value when it opens the file. The original file might contain 00123 even if the app displays 123.
First inspect a copy with a text viewer or the workbench. If the raw value still has its zeros, preserve that original export. Resaving a converted version can make the loss permanent in the new file.
Import identifiers as text
Microsoft documents importing CSV data and setting identifier columns to Text with its import tools. The exact controls depend on your Excel version and platform. Follow Microsoft's guide to leading zeros and large numbers for your environment, and verify a sample before saving.
Changing how a number is displayed is not the same as proving its original identifier. Formatting a value with five digits can display 00123, but that does not establish that five characters was the right code length.
Do not guess lost information
If the only available file contains 123, the tool cannot know whether the original was 123, 0123, 00123 or another code. Re-export from the authoritative system or consult a verified reference mapping.
What the comparison will show
With exact matching, an old key 00123 and a latest key 123 appear as missing and added records. That is a clue to investigate identifier formatting, not proof that one product was replaced by another.
Optional key trimming removes spaces at the edges; ignoring letter case affects letters. Neither option removes leading zeros. Field values also remain exact text, so formatting differences can still appear as changed values.
Check the downloaded report too
CSV reports can be interpreted again by the application used to open them. Import key columns as text and check several known identifiers. The exact JSON report preserves the parsed string values and avoids depending on a spreadsheet's display rules.
For formula-like cells, the CSV download adds an apostrophe prefix for safer viewing. This modifies those exported cells and is not a universal security guarantee across spreadsheet applications or repeated saves. Use JSON to retain exact values; do not enable formulas or external links in untrusted downloads.