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  • MySQL之表操作

    一、创建表

      1、创建新表

    #语法:
    create table 表名(
    字段名1 类型[(宽度) 约束条件],
    字段名2 类型[(宽度) 约束条件],
    字段名3 类型[(宽度) 约束条件]
    );
    
    #注意:
    1. 在同一张表中,字段名是不能相同
    2. 宽度和约束条件可选
    3. 字段名和类型是必须的
    mysql> create table auth(
        -> id int(10) primary key auto_increment,
        -> name varchar(10) not null,
        -> age int(3),
        -> birthday datetime
        -> );
    Query OK, 0 rows affected (0.36 sec)

      2、复制表

    mysql> create table auth2 select * from auth;
    Query OK, 0 rows affected (0.29 sec)
    Records: 0  Duplicates: 0  Warnings: 0

    二、查看表

      1、查看表结构

    mysql> desc auth;
    +----------+-------------+------+-----+---------+----------------+
    | Field    | Type        | Null | Key | Default | Extra          |
    +----------+-------------+------+-----+---------+----------------+
    | id       | int(10)     | NO   | PRI | NULL    | auto_increment |
    | name     | varchar(10) | NO   |     | NULL    |                |
    | age      | int(3)      | YES  |     | NULL    |                |
    | birthday | datetime    | YES  |     | NULL    |                |
    +----------+-------------+------+-----+---------+----------------+
    4 rows in set (0.02 sec)

      2、查看表的创建信息

    mysql> show create table auth;
    +-------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
    | Table | Create Table                                                                                                                                                                                                            |
    +-------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
    | auth  | CREATE TABLE `auth` (
      `id` int(10) NOT NULL AUTO_INCREMENT,
      `name` varchar(10) NOT NULL,
      `age` int(3) DEFAULT NULL,
      `birthday` datetime DEFAULT NULL,
      PRIMARY KEY (`id`)
    ) ENGINE=InnoDB DEFAULT CHARSET=utf8 |
    +-------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
    1 row in set (0.00 sec)
    

      

    三、修改表

      1、修改表名称

    mysql> alter table auth2 rename auth666;
    Query OK, 0 rows affected (0.10 sec)

      2、增加表字段

    mysql> alter table auth add addr char(6) not null;
    Query OK, 0 rows affected (0.53 sec)
    Records: 0  Duplicates: 0  Warnings: 0

      3、修改表字段

    修改表字段信息

    mysql> alter table auth modify addr varchar(6) null;
    Query OK, 0 rows affected (0.60 sec)
    Records: 0  Duplicates: 0  Warnings: 0

     修改表字段名以及字段信息

    mysql> alter table auth change addr address varchar(6);
    Query OK, 0 rows affected (0.09 sec)
    Records: 0  Duplicates: 0  Warnings: 0

      4.删除表字段

    mysql> alter table auth drop birthday;
    Query OK, 0 rows affected (0.49 sec)
    Records: 0  Duplicates: 0  Warnings: 0

    四、删除表

    mysql> drop table auth666;
    Query OK, 0 rows affected (0.10 sec)

    五、表的数据类型

    http://www.cnblogs.com/fu-yong/p/8495001.html

    六、表的约束

    http://www.cnblogs.com/fu-yong/p/8495003.html

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  • 原文地址:https://www.cnblogs.com/fu-yong/p/8494902.html
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