By using db<>fiddle, you agree to license everything you submit by Creative Commons CC0.
CREATE TABLE sourcetable (number_order INT, products_name CHAR(1))
INSERT INTO sourcetable (products_name) VALUES ('A'),('C'),('D'),('B')
SELECT *
FROM sourcetable
| number_order | products_name |
|---|---|
| null | A |
| null | C |
| null | D |
| null | B |
UPDATE sourcetable
SET number_order = (@tmp := @tmp + 1)
WHERE NOT (@tmp := 0)
ORDER BY products_name ASC
SELECT *
FROM sourcetable
| number_order | products_name |
|---|---|
| 1 | A |
| 3 | C |
| 4 | D |
| 2 | B |