Returns rows by un-nesting
A set of rows composed of the other expressions in the select list and either the elements of the array or the keys and values of the map.
expr is NULL no rows are produced.
explode can only be placed in the select list or a LATERAL VIEW.
When placing the function in the select list there must be no other generator function in the same select list.
The column produced by explode of an array is named
col by default, but can be aliased.
The columns for a map are by default called
They can also be aliased using an alias tuple such as
AS (myKey, myValue).