Amazon Redshift will no longer support the use of Python UDFs after June 30, 2026. We will start enforcing it in phases. For more information on the details of Python end of life and migration options, see the blog post that was published on June 30, 2025.

ST_M

ST_M returns the m coordinate of an input point.

Syntax

ST_M(point)

Arguments

Return type

DOUBLE PRECISION value of the m coordinate.

If point is null, then null is returned.

If point is a 2D or 3DZ point, then null is returned.

If point is the empty point, then null is returned.

If point is not a POINT, then an error is returned.

Examples

The following SQL returns the m coordinate of a point in a 3DM geometry.

SELECT ST_M(ST_GeomFromEWKT('POINT M (1 2 3)'));

st_m
-----------
 3                

The following SQL returns the m coordinate of a point in a 4D geometry.

SELECT ST_M(ST_GeomFromEWKT('POINT ZM (1 2 3 4)'));

st_m
-----------
 4