i think this is the most only MySQL clean way, atleast for MySQL versions under 8
Query
SET SESSION group_concat_max_len = @@max_allowed_packet;
SELECT
GROUP_CONCAT(
JSON_UNQUOTE(
JSON_EXTRACT(records.json, CONCAT('$[', number_generator.number , ']'))
FROM (
SELECT
@row := @row + 1 AS number
FROM (
SELECT 0 UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9
) row1
CROSS JOIN (
SELECT 0 UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9
) row2
CROSS JOIN (
SELECT @row := -1
) init_user_params
) AS number_generator
CROSS JOIN (
SELECT
, JSON_LENGTH(records.json) AS json_array_length
FROM (
SELECT
'["+63(02)3647766", "+63(02)5467329", "+63(02)8555522", "+63(02)3642403"]' AS json
) AS records
) AS records
WHERE
number BETWEEN 0 AND json_array_length - 1
