# Built-in Functions → average

**average()** is an aggregation function that returns the average of the values in a column.

## Signature

average(double expr, [groupBy(...)])

*expr*: expression evaluating to`double`

`groupBy`

: optional grouping function that specifies which group of data to operate over

Note

If you use the `groupBy`

function, you must include all the leading grouping dimensions in the **Insight** from the top-down to the level-based measure you want to evaluate. For more information, refer to Aggregation with a Level Based Measure.

## Returns

`double`

representing the average of the values in the column. If `groupBy`

is used, `average`

returns the average for each group.

## Examples

- Compute the average of the values in the data column
*AMOUNT_SOLD*.

average(Sales_Acme.Sales.AMOUNT_SOLD)

- Compute the average of
*AMOUNT_SOLD*by*QUARTER_NUMBER*.

average(Sales_Acme.Sales.AMOUNT_SOLD,groupBy(Sales_Acme.Sales.QUARTER_NUMBER))