reverse function
Applies to:  Databricks SQL 
 Databricks Runtime
Returns a reversed string or an array with reverse order of elements.
Syntax
reverse(expr)
Arguments
- expr: A- STRINGor- ARRAYexpression.
Returns
The result type matches the type of expr.
Examples
SQL
> SELECT reverse('Spark SQL');
 LQS krapS
> SELECT reverse(array(2, 1, 4, 3));
 [3,4,1,2]