Performs a union operation on a set of geography objects.
UnionAggregate ( geography_operand ) geography_operand
Is a geography type table column that holds the set of geography objects on which to perform a union operation.
SQL Server return type: geography
Method returns null if the input has different SRIDs. See Spatial Reference Identifiers (SRIDs).
Method ignores null inputs.
[!NOTE]
Method returns null if all inputted values are null.
The following example performs a UnionAggregate on a set of geography location points within a city.
USE AdventureWorks2012
GO
SELECT City,
geography::UnionAggregate(SpatialLocation) AS SpatialLocation
FROM Person.Address
WHERE PostalCode LIKE('981%')
GROUP BY City;