Postgres 13

By using db<>fiddle, you agree to license everything you submit by Creative Commons CC0.

CREATE TABLE files(
    formats JSONB
);


INSERT INTO files VALUES ('{
  "thumbnail": {
    "ext": ".jpg",
    "url": "https://some-url.com/image01.jpg",
    "name": "image01.jpg"
  }
}');
1 rows affected



UPDATE files 
SET formats = jsonb_set(formats, '{thumbnail,url}', CONCAT('"',REPLACE(formats->'thumbnail'->>'url','some-url','other-url'),'"')::JSONB)

1 rows affected

SELECT *
FROM files


formats


{"thumbnail": {"ext": ".jpg", "url": "https://other-url.com/image01.jpg", "name": "image01.jpg"}}