ALTER TABLE REFRESH ADD COLUMN created_at DATETIME DEFAULT CURRENT_TIMESTAMP, ADD COLUMN updated_at DATETIME DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP ALTER TABLE t1 ADD COLUMN created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP, ADD COLUMN updated_at DATETIME DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP;ALTER TABLE t1 ADD COLUMN createdAt TIMESTAMP DEFAULT CURRENT_TIMESTAMP, ADD COLUMN updatedAt DATETIME DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP; CREATE TABLE t1 ( created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP , updated_at DATETIME DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP );