From: http://blog.163.com/yaoyingying681@126/blog/static/109463675201191173221759/
MySQL 添加列,修改列,删除列的sql语句写法
ALTER TABLE:添加,修改,删除表的列,约束等表的定义。
- 查看列:desc 表名;
- 修改表名:alter table t_book rename to bbb;
- 添加列:alter table 表名 add column 列名 varchar(30);
- 删除列:alter table 表名 drop column 列名;
- 修改列名: alter table bbb change nnnnn hh int;
- 修改列属性:alter table t_book modify name varchar(22);
一,复制表结构
方法1:
mysql> create table a like users; //复制表结构
Query OK, 0 rows affected (0.50 sec)
mysql> show tables;
+----------------+
| Tables_in_test |
+----------------+
| a |
| users |
+----------------+
2 rows in set (0.00 sec)
mysql> create table a like users; //复制表结构
Query OK, 0 rows affected (0.50 sec)
mysql> show tables;
+----------------+
| Tables_in_test |
+----------------+
| a |
| users |
+----------------+
2 rows in set (0.00 sec)
方法2:
mysql> create table b select * from users limit 0; //复制表结构
Query OK, 0 rows affected (0.00 sec)
Records: 0 Duplicates: 0 Warnings: 0
mysql> show tables;
+----------------+
| Tables_in_test |
+----------------+
| a |
| b |
| users |
+----------------+
3 rows in set (0.00 sec)
mysql> create table b select * from users limit 0; //复制表结构
Query OK, 0 rows affected (0.00 sec)
Records: 0 Duplicates: 0 Warnings: 0
mysql> show tables;
+----------------+
| Tables_in_test |
+----------------+
| a |
| b |
| users |
+----------------+
3 rows in set (0.00 sec)
方法3:
mysql> show create table usersG; //显示创表的sql 这里也可以用 desc users;显示表的结构
*************************** 1. row ***************************
Table: users
Create Table: CREATE TABLE `users` ( //改表名
`ID` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
`user_name` varchar(60) NOT NULL DEFAULT '',
`user_pass` varchar(64) NOT NULL DEFAULT '',
PRIMARY KEY (`ID`)
) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8 //改auto_increment
1 row in set (0.00 sec)
mysql> show create table usersG; //显示创表的sql
*************************** 1. row ***************************
Table: users
Create Table: CREATE TABLE `users` ( //改表名
`ID` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
`user_name` varchar(60) NOT NULL DEFAULT '',
`user_pass` varchar(64) NOT NULL DEFAULT '',
PRIMARY KEY (`ID`)
) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8 //改auto_increment
1 row in set (0.00 sec)把sql语句copy出来,改一下表名和atuo_increment,然后在执行一下。
二,复制表数据,以及表结构
方法1:
mysql> create table c select * from users; //复制表的sql
Query OK, 4 rows affected (0.00 sec)
Records: 4 Duplicates: 0 Warnings: 0
mysql> create table c select * from users; //复制表的sql
Query OK, 4 rows affected (0.00 sec)
Records: 4 Duplicates: 0 Warnings: 0
方法2:
mysql> create table d select user_name,user_pass from users where id=1;
Query OK, 1 row affected (0.00 sec)
Records: 1 Duplicates: 0 Warnings: 0
mysql> create table d select user_name,user_pass from users where id=1;
Query OK, 1 row affected (0.00 sec)
Records: 1 Duplicates: 0 Warnings: 0上面的2种方法,方便,快捷,灵活性强。
方法3:
先创建一个空表, INSERT INTO 新表 SELECT * FROM 旧表 ,或者
INSERT INTO 新表(字段1,字段2,…….) SELECT 字段1,字段2,…… FROM 旧表
这种方法不是很方便,也是我以前经常用的。