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Legal Studies在 MySQL 中将 StudentName 列名更改为 FirstName？
将 CHANGE 用作 ALTER 语句。让我们首先创建一个表 -
mysql> create table DemoTable -> ( -> StudentName varchar(100), -> Age int -> ); Query OK, 0 rows affected (0.84 sec)
现在查看表的说明 -
mysql> desc DemoTable;
输出
这会产生以下输出 -
+----------------+--------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +----------------+--------------+------+-----+---------+-------+ | StudentName | varchar(100) | YES | | NULL | | | Age | int(11) | YES | | NULL | | +----------------+--------------+------+-----+---------+-------+ 2 rows in set (0.25 sec)
以下是用 ALTER 编写的查询 -
mysql> alter table DemoTable -> add column Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> add column CountryName varchar(100) after Age, -> change column StudentName FirstName varchar(200); Query OK, 0 rows affected (1.51 sec) Records: 0 Duplicates: 0 Warnings: 0
现在再次查看表的说明 -
mysql> desc DemoTable;
输出
这会产生以下输出 -
+-------------+--------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +-------------+--------------+------+-----+---------+----------------+ | FirstName | varchar(200) | YES | | NULL | | | Age | int(11) | YES | | NULL | | | CountryName | varchar(100) | YES | | NULL | | | Id | int(11) | NO | PRI | NULL | auto_increment | +-------------+--------------+------+-----+---------+----------------+ 4 rows in set (0.00 sec)
更新于: 30-6月-2020
139 次查看
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