st_m function

Applies to: Databricks Runtime 17.1 and above

Returns the M coordinate of the input point GEOMETRY, or NULL if the point is empty or does not have an M coordinate.

Syntax

st_m ( geoExpr )

Arguments

• geoExpr: A GEOMETRY value.

Returns

A value of type DOUBLE, M coordinate of the input point GEOMETRY.

The function returns NULL if the input is NULL or if the point is empty.

Examples

-- Returns the M coordinate of a non-empty point geometry with an M coordinate.
> SELECT st_m(st_geomfromtext('POINT M (2 3 4)'))
  4.0
-- Returns the M coordinate of a non-empty point geometry without an M coordinate.
> SELECT st_m(st_geomfromtext('POINT Z (1 2 3)'))
  NULL
-- Returns `NULL` for an empty point geometry.
> SELECT st_m(st_geomfromtext('POINT ZM EMPTY'))
  NULL

Related functions

• st_x function
• st_y function
• st_z function