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Applies to: 
Databricks SQL Databricks Runtime 17.1 and above
Important
This feature is in Public Preview.
Note
This feature is not available on Databricks SQL Classic warehouses. To learn more about Databricks SQL warehouses, see SQL warehouse types.
Returns the M coordinate of the input point GEOMETRY value, or NULL if the point is empty or does not have an M coordinate.
Syntax
st_m ( geoExpr )
Arguments
geoExpr: AGEOMETRYvalue.
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.
Error conditions
- If the value of
geoExpris not a point, the function returns ST_INVALID_ARGUMENT.INVALID_TYPE.
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