Sorting arrays

To create a sorted array of unique values from a set of rows, you can use the array_sort function, as in the following example.

WITH
dataset AS (
  SELECT ARRAY[3,1,2,5,2,3,6,3,4,5] AS items
)
SELECT array_sort(array_agg(distinct i)) AS array_items
FROM dataset
CROSS JOIN UNNEST(items) AS t(i)

This query returns:

+--------------------+
| array_items        |
+--------------------+
| [1, 2, 3, 4, 5, 6] |
+--------------------+

For information about expanding an array into multiple rows, see Flattening nested arrays.