array_max function
Applies to: 
Databricks SQL Databricks Runtime
Returns the maximum value in array.
Syntax
array_max(array)
Arguments
array: Any ARRAY with elements for which order is supported.
Returns
The result matches the type of the elements.
NULL elements are skipped.
If array is empty, or contains only NULL elements, NULL is returned.
Examples
SQL
> SELECT array_max(array(1, 20, NULL, 3));
20