# ST\_Union

An aggregation function that returns a MULTI geometry or NON-MULTI geometry from a set of geometries. It ignores NULL geometries.

## Signature

> ST\_Union(geometry\[])

## Usage Examples

These examples are based on the [Streaming Quick Start](https://docs.pinot.apache.org/release-1.2.0/basics/getting-started/quick-start#streaming).

```sql
select group_city, ST_AsText(STUnion(location)) AS unionString
from meetupRsvp 
GROUP BY group_city
ORDER BY STUnion(location) DESC
LIMIT 5
```

| group\_city | unionString                                                                                                                                                                                                                                                                                                                                    |
| ----------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| London      | MULTIPOINT ((-0.21 51.54), (-0.19 51.5), (-0.19 51.56), (-0.18 51.49), (-0.18 51.51), (-0.18 51.52), (-0.16 51.52), (-0.14 51.54), (-0.13 51.5), (-0.13 51.51), (-0.13 51.52), (-0.13 51.53), (-0.12 51.51), (-0.12 51.53), (-0.11 51.53), (-0.1 51.5), (-0.1 51.52), (-0.09 51.5), (-0.09 51.52), (-0.07 51.52), (-0.02 51.49), (0.06 51.51)) |
| New York    | MULTIPOINT ((-74 40.72), (-74 40.74), (-73.99 40.73), (-73.99 40.75), (-73.99 40.76), (-73.98 40.75), (-73.98 40.79), (-73.97 40.75), (-73.94 40.81))                                                                                                                                                                                          |
| Austin      | MULTIPOINT ((-97.76 30.24), (-97.75 30.22), (-97.74 30.27), (-97.74 30.32), (-97.73 30.35), (-97.71 30.27), (-97.71 30.38), (-97.71 30.42))                                                                                                                                                                                                    |
| Denver      | MULTIPOINT ((-105.08 39.7), (-105.01 39.77), (-104.99 39.75), (-104.98 39.73), (-104.96 39.68), (-104.93 39.7), (-104.92 39.68))                                                                                                                                                                                                               |
| Atlanta     | MULTIPOINT ((-84.47 33.86), (-84.44 33.79), (-84.4 33.86), (-84.39 33.75), (-84.38 33.77), (-84.32 33.82), (-84.25 33.89))                                                                                                                                                                                                                     |


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