st_z function

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 Z coordinate of the input point GEOMETRY value, or NULL if the point is empty or does not have a Z coordinate.

Syntax

st_z ( geoExpr )

Arguments

• geoExpr: A GEOMETRY value.

Returns

A value of type DOUBLE, equal to the Z coordinate of the input point GEOMETRY value.

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

Error conditions

• If the value of geoExpr is not a point, the function returns ST_INVALID_ARGUMENT.INVALID_TYPE.

Examples

-- Returns the Z coordinate of a non-empty point geometry with a Z coordinate.
> SELECT st_z(st_geomfromtext('POINT Z (1 2 3)'));
  3.0
-- Returns the Z coordinate of a non-empty point geometry without a Z coordinate.
> SELECT st_z(st_geomfromtext('POINT M (2 3 4)'));
  NULL
-- Returns `NULL` for an empty point geometry.
> SELECT st_z(st_geomfromtext('POINT ZM EMPTY'));
  NULL

Related functions

• st_m function
• st_x function
• st_y function
• st_zmax function
• st_zmin function