在MySQL中使用CHANGE命令的目的？
MySQL中的CHANGE命令用于重命名列名。让我们首先创建一个表-
create table DemoTable796 ( StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY,Name varchar(100),StudentAge int );
让我们检查表的描述-
desc DemoTable796;
这将产生以下输出-
+------------+--------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +------------+--------------+------+-----+---------+----------------+ | StudentId | int(11) | NO | PRI | NULL | auto_increment | | Name | varchar(100) | YES | | NULL | | | StudentAge | int(11) | YES | | NULL | | +------------+--------------+------+-----+---------+----------------+ 3 rows in set (0.00 sec)
以下是在MySQL中使用CHANGE命令的查询-
alter table DemoTable796 change Name StudentName varchar(100); Records: 0 Duplicates: 0 Warnings: 0
让我们再次检查表的描述-
desc DemoTable796;
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 | | | StudentAge | int(11) | YES | | NULL | | +-------------+--------------+------+-----+---------+----------------+ 3 rows in set (0.00 sec)