array_compact function
Applies to: 
Databricks SQL Databricks Runtime 12.2 LTS and above
Removes NULL elements from array.
Syntax
array_compact(array)
Arguments
array: An ARRAY expression.
Returns
The function returns an array of the same type as the input argument where all NULL values have been removed.
Examples
SQL
> SELECT array_compact(array(1, 2, NULL, 3, NULL, 3));
[1, 2, 3, 3]
> SELECT array_compact(array(NULL, NULL));
[]