# MI_AggregateUnion

## Description

Returns a geometry object which represents the union of an aggregated set of geometry objects.

## Syntax

MI_AggregateUnion ( geometry )

## Arguments

`geometry` is an expression which returns a geometry.

## Example

Returns a geometry object which represents the union of an aggregated set of country geometries.

`select MI_AggregateUnion([Geometry_Column]) from countries where country in ('Canada','Brazil','Argentina','Greenland')`