MySQL 8.0

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select version();

version()

8.0.30

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

ALTER TABLE re MODIFY column `mydate` DATETIME NOT NULL

Records: 0  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 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci