Postgres 14

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CREATE TABLE example(data) AS (VALUES
  ('{"foo": [1,2,3,4]}'::jsonb),
  ('{"foo": [10,20,30,40,50,60]}')
);
TABLE example;

SELECT 2

data

{"foo": [1, 2, 3, 4]}

{"foo": [10, 20, 30, 40, 50, 60]}

SELECT 2

SELECT ARRAY(
   SELECT elem::int
   FROM jsonb_array_elements(data -> 'foo') elem
) AS arr
FROM example;

arr

{1,2,3,4}

{10,20,30,40,50,60}

SELECT 2

SELECT (
  SELECT array_agg((a, b) ORDER BY o)
  FROM (
    SELECT elem::int AS a, lead(elem::int) OVER (ORDER BY o) AS b, o
    FROM jsonb_array_elements(data -> 'foo') WITH ORDINALITY els(elem, o)
  ) AS pairs
  WHERE o % 2 = 1
) AS arr
FROM example;

arr

{"(1,2)","(3,4)"}

{"(10,20)","(30,40)","(50,60)"}

SELECT 2