Warnings about IDs, currency and percentages
When a column is marked as an ID, a currency or a percentage, Mammoth questions choices that are probably a mistake, such as summing order IDs. The warnings never block Apply. To set or change a column's meaning, see Column types, IDs, currency and percentages.
Every warning and where it appears
Summing or averaging an ID adds up codes, and summing percentages rarely means anything, so some functions question a choice that is probably a mistake. Each warning starts with the column name in bold, such as "order_id is an ID." None of them blocks Apply.
| Where | Warning | When |
|---|---|---|
| Explore card Show values by, Group & Pivot task | "Adding or averaging it adds up the codes. Did you mean Count distinct?" | Sum or Average of an ID column. Group & Pivot offers Swap to Count distinct or Keep. |
| Explore card Show values by, Group & Pivot task | "Adding percentages rarely means anything. Did you mean Average?" | Sum of a Percentage column. Group & Pivot offers Swap to Average or Keep. |
| Create Metric from a column header | "Sum adds up the codes." or "Average of the codes is not a quantity." | Sum or Average of an ID column |
| Create Metric from a column header | "Adding percentages rarely means anything. Average usually does." | Sum of a Percentage column |
| Math Function | "IDs are labels, not amounts, so doing arithmetic on them isn't meaningful." | A formula (in Formula mode) uses an ID column. |
| Math Function | "This formula mixes an amount of money with a percentage. Check that the result is what you mean." | A formula (in Formula mode) uses a Currency and a Percentage column together. |
| Window Function | "IDs are labels, not amounts, so a running total or ranking of them isn't meaningful." | A sum, average or ranking runs over an ID column. |
| Join, Lookup | Key type and meaning warnings | The keys are stored as different types, one is an ID and the other isn't, or they are in different currencies. See Join two datasets on a shared column. |
| Unpivot | "The new value column does not carry over the meaning of the columns you stack (an ID, a currency or a percentage). It starts as a plain column." | A stacked column has a meaning. |
In Group & Pivot, Keep dismisses the warning for that aggregation and keeps your choice. When you pick a column for Sum or Average in an Explore card, ID columns are listed last with the hint "it's an ID". Data Check also suggests checks for ID, Percentage and Currency columns.
Related
- Column types, IDs, currency and percentages: change a column's type or meaning.
- Group, pivot and unpivot: where the Sum and Average warnings appear.
- Calculate with formulas: Math Function and Window Function warnings.
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