In Trino (Presto) SQL, how do you convert a varchar (string) to an array of characters (char)?

Question

I want to create a array of characters from a varchar field. For example, from 'test', I want to have ARRAY['t', 'e', 's', 't'].

Answer 1

Here's one way:

SELECT REGEXP_EXTRACT_ALL('test', '.') AS letters;

returns:

#	letters
1	["t","e","s","t",""]