Amazon Athena
User Guide  | API Reference

Converting Array Data Types

To convert data in arrays to supported data types, use the CAST operator, as CAST(value AS type). Athena supports all of the native Presto data types.

SELECT
   ARRAY [CAST(4 AS VARCHAR), CAST(5 AS VARCHAR)]
AS items

This query returns:

+-------+
| items |
+-------+
| [4,5] |
+-------+

Create two arrays with key-value pair elements, convert them to JSON, and concatenate, as in this example:

SELECT
   ARRAY[CAST(MAP(ARRAY['a1', 'a2', 'a3'], ARRAY[1, 2, 3]) AS JSON)] ||
   ARRAY[CAST(MAP(ARRAY['b1', 'b2', 'b3'], ARRAY[4, 5, 6]) AS JSON)]
AS items

This query returns:

+--------------------------------------------------+
| items                                            |
+--------------------------------------------------+
| [{"a1":1,"a2":2,"a3":3}, {"b1":4,"b2":5,"b3":6}] |
+--------------------------------------------------+