docs/api/sql/Aggregate-Functions/ST_Collect_Agg.md

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# ST_Collect_Agg

Introduction: Collects all geometries in a geometry column into a single multi-geometry (MultiPoint, MultiLineString, MultiPolygon, or GeometryCollection). Unlike `ST_Union_Agg`, this function does not dissolve boundaries between geometries - it simply collects them into a multi-geometry.

![ST_Collect_Agg](../../../image/ST_Collect_Agg/ST_Collect_Agg.svg "ST_Collect_Agg")

Format: `ST_Collect_Agg (A: geometryColumn)`

Return type: `Geometry`

Since: `v1.8.1`

SQL Example

```sql
SELECT ST_Collect_Agg(geom) FROM (
  SELECT ST_GeomFromWKT('POINT(1 2)') AS geom
  UNION ALL
  SELECT ST_GeomFromWKT('POINT(3 4)') AS geom
  UNION ALL
  SELECT ST_GeomFromWKT('POINT(5 6)') AS geom
)
```

Output:

```
MULTIPOINT ((1 2), (3 4), (5 6))
```

SQL Example with GROUP BY

```sql
SELECT category, ST_Collect_Agg(geom) FROM geometries GROUP BY category
```