Minumum, maximum and first and last from group without `first` and `last` in mysql (it doesn't have them)

min_max_open_close

create table `values` (
     id integer unsigned primary key auto_increment,
     value double,
     `time` time
);

insert into `values` (time, value) values
  ('00:00:01', 3),
  ('00:00:02', 2),
  ('00:00:03', 1),
  ('00:01:01', 4),
  ('00:01:02', 5),
  ('00:01:03', 6);

SELECT
    vs1.value as `open`,
    vs2.value as `close`,
    te.minv as `min`,
    te.maxv as `max`
FROM 
(
  SELECT 
    MIN(time) as mint,
    MAX(time) as maxt,
    MIN(value) as minv,
    MAX(value) as maxv 
  FROM `values`
  GROUP BY hour(time), minute(time)
) as te
JOIN `values` vs1 ON vs1.time = te.mint
JOIN `values` vs2 ON vs2.time = te.maxt
ORDER BY vs1.time;