Online Tool Store
Column Statistics Comparator
Column Statistics Comparator finds where two snapshots diverge; the null rate column is usually where the real problem shows first.
🔒 This tool runs entirely in your browser. Your files are never uploaded to a server.
Data & CSV
Column Statistics Comparator
Frontend preview — no upload or external service.
Column comparison
amount: mean up 3%, nulls up from 0.2% to 11.4%, distinct values down 40%. The null rate jump is the finding — a source field stopped populating.
How the Column Statistics Comparator works
- Paste both datasets with matching headers — last month and this month, or before and after a pipeline change.
- Set the threshold above which a difference is worth flagging.
- Look at null rate and cardinality before the mean. A mean can drift for real reasons; a null rate tripling almost never does.
FAQ
What changes matter most?
Null rate and distinct-value count. A mean shifting a few percent is often genuine, while a null rate jumping from near zero is nearly always a broken join or a renamed source field.
Does this detect data drift?
It compares two snapshots, which is the manual version. Continuous drift monitoring needs a pipeline that runs these comparisons on a schedule and alerts on the thresholds.
What if the columns don't match?
Columns present in one dataset and not the other are listed separately. That mismatch is itself a finding — a schema change nobody announced.
How we compare
| Feature | Online Tool Store | A spreadsheet | A BI platform |
|---|---|---|---|
| Null and cardinality shifts | ✓ | Manual | ✓ |
| Threshold flagging | ✓ | ✗ | ✓ |
| Nothing uploaded | ✓ | ✓ | ✗ |
| No install | ✓ | ✓ | ✗ |
Column Statistics Comparator finds where two snapshots diverge; the null rate column is usually where the real problem shows first.