> For the complete documentation index, see [llms.txt](https://docs.cascade.io/cascade/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.cascade.io/cascade/functions-and-expressions/functions/aggregate/sumby.md).

# SUMBY

SUMBY( `column`, `partition column` )

Sums the values within a `column` when grouped by unique values within a `partition column`

{% hint style="info" %}
SUMBY() is a [**window function**](/cascade/functions-and-expressions/building-expressions/guide-to-window-functions.md)**,** which performs SUM() except partitioned by the unique values of a separate column.
{% endhint %}

### Arguments

| Arguments          | Description                     |
| ------------------ | ------------------------------- |
| `column`           | Column to sum                   |
| `partition column` | Column containing unique values |

### Output

Outputs a sum of values when grouped by `partition column`

### Example

{% embed url="<https://datawrapper.dwcdn.net/OkzGI/1/>" %}