> For the complete documentation index, see [llms.txt](https://docs.pentaho.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.pentaho.com/pdia-data-integration/9.3-data-integration/pdi-transformation-steps-reference-overview/group-by-landing-page-article/select-an-engine-group-by/using-group-by-on-pentaho-engine-article/general-group-by-kettle/aggregates-table-group-by-kettle.md).

# Aggregates table

The **Aggregates** table specifies the group you want to aggregate, the aggregation method, and the name of the resulting new field.

The **Aggregates** table contains the following columns:

| Column      | Description                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |
| ----------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| **Name**    | The name of the aggregate field.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
| **Subject** | The subject on which you want to use an aggregation method.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |
| **Type**    | <p>The aggregate method.</p><p>The aggregation methods are:</p><ul><li>Sum</li><li>Average (Mean)</li><li>Median</li><li>Percentile (linear interpolation)</li><li>Minimum</li><li>Maximum</li><li>Number of values (N)</li><li>Concatenate strings separated by , (comma)</li><li>First non-null value</li><li>Last non-null value</li><li>First value (including null)</li><li>Last value (including null)</li><li>Cumulative sum (all rows option only)</li><li>Cumulative average (all rows option only)</li><li>Standard deviation (Population)</li><li>Concatenate strings that are separated by the character specified in the <strong>Value</strong> column</li><li>Number of distinct values</li><li>Number of rows (without field argument)</li><li>Standard deviation (sample)</li><li>Percentile (nearest-rank method).</li></ul> |
| **Value**   | The aggregate value.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |


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