MySQL Transponse and redesign the table

[inna]

The table is as follows:

ts	choice_one	choice_two	correct_one	correct_two
111	ok	ok	ok	crit
222	ok	ok	ok	ok

A request for SQL is required and is based on the following:

ts	category	choice	correct
111	one	ok	ok
111	two	ok	crit
222	one	ok	ok
222	two	ok	ok

Description of developments

Columns of choice and correct (was part of the headings), and one and two (second part of the headings) shall be assigned to the new column category. At the intersection, their respective values remain.

In the working table of some 20 categories one, two, three, etc. (the names are known in advance), for each of which there is a choice - correct (factic and correct marking of categories, respectively) of about 40 columns. We have to do this as a vertical decoration when there are only four above-mentioned columns, but the number of lines will increase.

[Analeea]

With Akina's clue, I got a decision. We use UNION ALL, or in my case UNION (UNION ALL + DISTINCT)

CREATE TABLE mytable (
  ts INT,
  choice_one varchar(50),
  choice_two varchar(50),
  etalon_one varchar(50),
  etalon_two varchar(50)
);
INSERT INTO mytable (ts, choice_one, choice_two, etalon_one, etalon_two) VALUES

('111', 'ok', 'ok', 'ok', 'crit'),

('222', 'ok', 'ok', 'ok', 'ok');
SELECT ts, choice_one AS choice, 'one' AS category

FROM mytable

UNION

SELECT ts, choice_two AS choice, 'two' AS category

FROM mytable

UNION

SELECT ts, etalon_one AS correct, 'one' AS category

FROM mytable

UNION

SELECT ts, etalon_two AS correct, 'two' AS category

FROM mytable

Depending on the case, it can put choise and correct in one column. In my case, it's doubled.