使用DEFAULT CURRENT_TIMESTAMP和ON UPDATE CURRENT_TIMESTAMP时，列具有默认值的当前时间戳，并自动更新为当前时间戳。
让我们看一个例子并创建一个表-mysql> create table DemoTable737 (
StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY,
StudentName varchar(100),
StudentAdmissiondate datetime
);
以下是对MySQL中的CURRENT_TIMESTAMP和ON UPDATE CURRENT_TIMESTAMP的查询-mysql> alter table DemoTable737 modify column StudentAdmissiondate
timestamp DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP;
Records: 0 Duplicates: 0 Warnings: 0
让我们再次检查表的描述-mysql> desc DemoTable737;
这将产生以下输出-+----------------------+--------------+------+-----+-------------------+-----------------------------+
| Field | Type | Null | Key | Default | Extra |
+----------------------+--------------+------+-----+-------------------+-----------------------------+
| StudentId | int(11) | NO | PRI | NULL | auto_increment |
| StudentName | varchar(100) | YES | | NULL | |
| StudentAdmissiondate | timestamp | YES | | CURRENT_TIMESTAMP | on update CURRENT_TIMESTAMP |
+----------------------+--------------+------+-----+-------------------+-----------------------------+
3 rows in set (0.01 sec)
| 
转播
