Re: Selecting a JSON object of arrays from a PostgreSQL table

Also got this nice suggestion at https://stackoverflow.com/q/48050127/165071 -

SELECT COALESCE(
  json_object_agg(
          gid, array_to_json(y)
        ), '{}'::json)
FROM    (
  SELECT  gid,
          array_agg(
            json_build_object(
              'uid', uid,
              'created', EXTRACT(EPOCH FROM created)::int,
              'msg', msg)
          ) AS y
  FROM    chat /* WHERE gid = 0 */
  GROUP BY gid
) x;