st_zmax function
Applies to: 
Databricks SQL Databricks Runtime 17.1 and above
Preview
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nota
This feature is not available on Databricks SQL Classic warehouses. To learn more about Databricks SQL warehouses, see SQL warehouse types
Returns the maximum Z coordinate of the input GEOMETRY, or NULL if the geometry is empty or does not have a Z coordinate.
Syntax
st_zmax ( geoExpr )
Arguments
geoExpr: AGEOMETRYvalue.
Returns
A value of type DOUBLE, maximum Z coordinate of the input GEOMETRY.
The function returns NULL if the input is NULL or if the geometry is empty or does not have a Z coordinate.
Examples
SQL
-- Returns the maximum Z coordinate of a non-empty geometry with a Z coordinate.
> SELECT st_zmax(st_geomfromtext('LINESTRING Z (10 34 -1,44 57 -2,30 24 -5)'));
-1.0
-- Returns `NULL` for a non-empty geometry without a Z coordinate.
> SELECT st_zmax(st_geomfromtext('LINESTRING(10 34,44 57,30 24)'));
NULL