docs/api/sql/Aggregate-Functions/ST_3DExtent.md

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# ST_3DExtent

Introduction: Return the 3D bounding box of all geometries in `A` as a typed [Box3D](../box3d/Box3D-Functions.md). Empty geometries and null values are skipped. If all inputs are empty or null, the result is null. Geometries without a Z dimension fold into `z = 0`. Mirrors PostGIS `ST_3DExtent`.

`ST_3DExtent` is the 3D counterpart to [ST_Extent](ST_Extent.md), which returns a `Box2D`.

![ST_3DExtent aggregates a column of geometries into the enclosing cuboid](../../../image/box3d/st_3dextent.svg "ST_3DExtent: enclosing cuboid over a column")

Format: `ST_3DExtent(A: geometryColumn)`

Return type: `Box3D`

Since: `v1.9.1`

SQL Example

```sql
SELECT ST_AsText(ST_3DExtent(geom))
FROM VALUES
    (ST_GeomFromText('POINT Z (1 2 3)')),
    (ST_GeomFromText('POINT Z (4 5 -1)')),
    (ST_GeomFromText('LINESTRING (-3 0, 0 0)')) AS t(geom)
```

Output:

```
BOX3D(-3.0 0.0 -1.0, 4.0 5.0 3.0)
```

The XY-only linestring contributes `z = 0`, which sits between the `-1` and `3` of the two POINT Z rows, so it does not move either Z bound.