MySQL 8.0

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

select version();

version()

8.0.30

CREATE TABLE re ( 
   file_id INT NOT NULL AUTO_INCREMENT PRIMARY KEY, 
   mydate DATE NOT NULL
  );

INSERT INTO re (mydate) VALUES  
    ('2022-12-21'),
    ('2022-12-24'),
    ('2022-12-25'),
    ('2022-12-31')
    ;

Records: 4  Duplicates: 0  Warnings: 0

ALTER TABLE re MODIFY column `mydate` DATETIME NOT NULL

Records: 4  Duplicates: 0  Warnings: 0

SHOW CREATE TABLE re;

Table
Create Table

re
CREATE TABLE `re` (
  `file_id` int NOT NULL AUTO_INCREMENT,
  `mydate` datetime NOT NULL,
  PRIMARY KEY (`file_id`)
) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci

SELECT * FROM re;

file_id
mydate

1
2022-12-21 00:00:00

2
2022-12-24 00:00:00

3
2022-12-25 00:00:00

4
2022-12-31 00:00:00

file_id	mydate
1	2022-12-21 00:00:00
2	2022-12-24 00:00:00
3	2022-12-25 00:00:00
4	2022-12-31 00:00:00