Amazon Redshift will no longer support the creation of new Python UDFs starting November 1, 2025. If you would like to use Python UDFs, create the UDFs prior to that date. Existing Python UDFs will continue to function as normal. For more information, see the blog post .

ST_ZMin

ST_ZMin returns the minimum z coordinate of an input geometry.

Syntax

ST_ZMin(geom)

Arguments

Return type

DOUBLE PRECISION value of the minimum z coordinate.

If geom is empty, then null is returned.

If geom is null, then null is returned.

If geom is a 2D or 3DM geometry, then null is returned.

Examples

The following SQL returns the smallest z coordinate of a linestring in a 3DZ geometry.

SELECT ST_ZMin(ST_GeomFromEWKT('LINESTRING Z (0 1 2, 3 4 5, 6 7 8)'));

st_zmin
-----------
  2               

The following SQL returns the smallest z coordinate of a linestring in a 4D geometry.

SELECT ST_ZMin(ST_GeomFromEWKT('LINESTRING ZM (0 1 2 3, 4 5 6 7, 8 9 10 11)'));

st_zmin
-----------
  2