ST_MMin

Introduction: Returns M minima of the given geometry or null if there is no M coordinate.

Format: ST_MMin(geom: Geometry)

Since: v1.6.1

SQL Example:

SELECT ST_MMin(
        ST_GeomFromWKT('LINESTRING ZM(1 1 1 1, 2 2 2 2, 3 3 3 3, -1 -1 -1 -1)')
)

Output:

-1.0