# 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. The field name cannot contain spaces, dashes, or special characters, and must start with a letter.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
| **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 (not available with <strong>Include All Rows</strong>)</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.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET 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-spark-engine-article/general-group-by-spark/aggregates-table-group-by-spark.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.
