Couldn't alter field with default value for make it not nullable.

CREATE TABLE `table2` (

  `i1` INT(10) UNSIGNED NOT NULL,

  `d1` TIMESTAMP NULL DEFAULT NULL

) ENGINE=INNODB;

INSERT INTO table2 (i1) VALUES (1), (2), (3), (4), (5);

ALTER TABLE `table2`   

  CHANGE `d1` `d1` TIMESTAMP DEFAULT CURRENT_TIMESTAMP  NOT NULL

Error Code: 1138

Invalid use of NULL value

SELECT @@sql_mode

@@sql_mode                                                                                                                 

---------------------------------------------------------------------------------------------------------------------------

NO_BACKSLASH_ESCAPES,STRICT_ALL_TABLES,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION