How to use the Compare CSV Files
- 1 Drop the older file first (it is the source), then the newer file.
- 2 In the compare step choose the other file and the key column(s) that identify a row, such as an id or SKU.
- 3 Read the list: removed rows, added rows and changed cells with their old and new value.
- 4 Download the differences as CSV or Excel.
A list of differences, not two colours
A line-by-line diff is the wrong tool for tables: one inserted row shifts everything below it, and reordered rows look like total change. Comparing by key matches each row to its counterpart first. A row only in the old file is reported as removed, a row only in the new file as added, and for matched rows each cell that differs is listed with the column, the old and the new value.
The result is itself a table, so you can sort it, filter it (“show only changes in the price column”) and export it. For rows that were added or removed the other values are summarised as column: value pairs.
Control what counts as different
Ignore upper and lower case, ignore spaces around values, and treat 1.0 and 1 as equal when you compare numbers. Compare all shared columns or only those you pick. Columns that exist in only one file are reported, not silently skipped. When a key occurs more than once, the first occurrence in one file is compared with the first in the other, and you are told.
No key?
Without a key column rows are compared by position – row 5 with row 5 – which only makes sense if both files list the same things in the same order.
Limits
Both files are read with automatic settings and must have a header row. To compare two texts or documents line by line, use compare text files.
Frequently asked questions
Can I compare an Excel file with a CSV?
Yes, each file is read on its own, so the formats can differ.
What if the key is made of two columns?
Tick both; rows are matched when both values are the same.
Does it show cell-level changes for added rows?
Added and removed rows are listed once, with their values on one line. Cell-level changes are listed for rows present in both files.
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