CentOS6.5下简单的MySQL数据库操作

1.登录成功之后退出的话，直接输入quit或者exit即可。

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2.使用.tar.gz的包安装MySQL时，进入MySQL需要使用绝对路径

[root@winner ~]# /usr/local/mysql/bin/mysql -uroot

单独只是输入一个"mysql" 命令是不行的，因为"/usr/local/mysql/bin" 没有在 PATH 这个环境变量里(使用yum安装不需要)。如何把它加入环境变量PATH中？

[root@winner ~]# PATH=$PATH:/usr/local/mysql/bin

这样就可以了，但重启Linux后还会失效，所以需要让它开机加载:

[root@winner ~]# echo "PATH=$PATH:/usr/local/mysql/bin" >> /etc/profile
[root@winner ~]# source /etc/profile
[root@localhost ~]# mysql -uroot

-u 用来指定要登录的用户，后边可以有空格，也可以无空格。-p 后面可以直接跟密码，后面不可以有空格，不过密码最好用单引号括起来，不括也可以，但是密码中如果有特殊字符就会有问题了，所以最好是括起来。

连接数据库

通过使用 mysql -u root -p 可以连接数据库，但这只是连接的本地的数据库"localhost", 可是有很多时候都是去连接网络中的某一个主机上的mysql。

[root@winner ~]# mysql -uroot -p -h192.168.137. -P3306
Enter password:

其中后边的 -P(大写) 用来指定远程主机MySQL的绑定端口，默认都是3306, -h 用来指定远程主机的IP.

一些基本的MySQL操作命令

1. 查询当前的库

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| test               |
| winner             |
+--------------------+
rows in set (0.07 sec)

2. 查询某个库的表

首先需要切换到某个库中
mysql> use mysql
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
 
显示该数据库中的表
mysql> show tables;
+---------------------------+
| Tables_in_mysql           |
+---------------------------+
| columns_priv              |
| db                        |
| event                     |
| func                      |
| general_log               |
| help_category             |
| help_keyword              |
| help_relation             |
| help_topic                |
| host                      |
| ndb_binlog_index          |
| plugin                    |
| proc                      |
| procs_priv                |
| servers                   |
| slow_log                  |
| tables_priv               |
| time_zone                 |
| time_zone_leap_second     |
| time_zone_name            |
| time_zone_transition      |
| time_zone_transition_type |
| user                      |
+---------------------------+
rows in set (0.00 sec)

3. 查看某个表的全部字段

mysql> desc host;
+-----------------------+---------------+------+-----+---------+-------+
| Field                 | Type          | Null | Key | Default | Extra |
+-----------------------+---------------+------+-----+---------+-------+
| Host                  | char()      | NO   | PRI |         |       |
| Db                    | char()      | NO   | PRI |         |       |
| Select_priv           | enum('N','Y') | NO   |     | N       |       |
| Insert_priv           | enum('N','Y') | NO   |     | N       |       |
| Update_priv           | enum('N','Y') | NO   |     | N       |       |
| Delete_priv           | enum('N','Y') | NO   |     | N       |       |
| Create_priv           | enum('N','Y') | NO   |     | N       |       |
| Drop_priv             | enum('N','Y') | NO   |     | N       |       |
| Grant_priv            | enum('N','Y') | NO   |     | N       |       |
| References_priv       | enum('N','Y') | NO   |     | N       |       |
| Index_priv            | enum('N','Y') | NO   |     | N       |       |
| Alter_priv            | enum('N','Y') | NO   |     | N       |       |
| Create_tmp_table_priv | enum('N','Y') | NO   |     | N       |       |
| Lock_tables_priv      | enum('N','Y') | NO   |     | N       |       |
| Create_view_priv      | enum('N','Y') | NO   |     | N       |       |
| Show_view_priv        | enum('N','Y') | NO   |     | N       |       |
| Create_routine_priv   | enum('N','Y') | NO   |     | N       |       |
| Alter_routine_priv    | enum('N','Y') | NO   |     | N       |       |
| Execute_priv          | enum('N','Y') | NO   |     | N       |       |
| Trigger_priv          | enum('N','Y') | NO   |     | N       |       |
+-----------------------+---------------+------+-----+---------+-------+
rows in set (0.00 sec)

也可以使用另一条命令，显示比这个更详细，而且可以把建表语句全部列出来:

mysql> show create table host\G;
*************************** . row ***************************
       Table: host
Create Table: CREATE TABLE `host` (
  `Host` char() COLLATE utf8_bin NOT NULL DEFAULT '',
  `Db` char() COLLATE utf8_bin NOT NULL DEFAULT '',
  `Select_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
  `Insert_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
  `Update_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
  `Delete_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
  `Create_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
  `Drop_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
  `Grant_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
  `References_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
  `Index_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
  `Alter_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
  `Create_tmp_table_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
  `Lock_tables_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
  `Create_view_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
  `Show_view_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
  `Create_routine_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
  `Alter_routine_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
  `Execute_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
  `Trigger_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
  PRIMARY KEY (`Host`,`Db`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8 COLLATE=utf8_bin COMMENT='Host privileges;  Merged with database privileges'
row in set (0.00 sec)

4. 查看当前是哪个用户

mysql> select user();
+----------------+
| user()         |
+----------------+
| root@localhost |
+----------------+
row in set (0.00 sec)

5. 查看当前所使用数据库

mysql> select database();
+------------+
| database() |
+------------+
| mysql      |
+------------+
row in set (0.00 sec)

6. 创建一个新库

mysql> create database db1;
Query OK,  row affected (0.02 sec)

7. 创建一个新表

mysql> create table t1 (`id` int(), `name` char());
Query OK,  rows affected (0.02 sec)

8. 查看当前数据库版本

mysql> select version();
+-----------+
| version() |
+-----------+
| 5.1.    |
+-----------+
row in set (0.00 sec)

9. 查看当前MySQL状态

mysql> show status;
+-----------------------------------+----------+
| Variable_name                     | Value    |
+-----------------------------------+----------+
| Aborted_clients                   |         |
| Aborted_connects                  |         |
| Binlog_cache_disk_use             |         |
| Binlog_cache_use                  |         |
| Bytes_received                    |      |
| Bytes_sent                        |     |
| Com_admin_commands                |         |
| Com_assign_to_keycache            |         |
| Com_alter_db                      |         |
| Com_alter_db_upgrade              |         |
| Com_alter_event                   |         |

10. 查看MySQL的参数

mysql> show variables;
+-----------------------------------------+---------------------+
| Variable_name                           | Value               |
+-----------------------------------------+---------------------+
| auto_increment_increment                |                    |
| auto_increment_offset                   |                    |
| autocommit                              | ON                  |
| automatic_sp_privileges                 | ON                  |
| back_log                                |                   |
| basedir                                 | /usr/local/mysql/   |

11. 修改MySQL的参数

mysql> show variables like 'max_connect%';
+--------------------+-------+
| Variable_name      | Value |
+--------------------+-------+
| max_connect_errors |     |
| max_connections    |    |
+--------------------+-------+
rows in set (0.00 sec)
 
mysql> set global max_connect_errors = ;
Query OK,  rows affected (0.00 sec)
 
mysql> show variables like 'max_connect_errors';
+--------------------+-------+
| Variable_name      | Value |
+--------------------+-------+
| max_connect_errors |   |
+--------------------+-------+
row in set (0.00 sec)

在MySQL命令行， "%"类似于shell下的 *, 表示万能匹配。使用 "set global" 可以临时修改某些参数，但是重启mysqld服务后还会变为原来的，所以要想恒久生效，需要在配置文件 my.cnf 中定义。

12. 查看当前MySQL服务器的队列

这个在日常的管理工作中使用最为频繁，因为使用它可以查看当前mysql在干什么，可以发现是否有锁表:

mysql> show processlist;
+----+------+-----------+------+---------+------+-------+------------------+
| Id | User | Host      | db   | Command | Time | State | Info             |
+----+------+-----------+------+---------+------+-------+------------------+
|   | root | localhost | db1  | Query   |     | NULL  | show processlist |
+----+------+-----------+------+---------+------+-------+------------------+
row in set (0.00 sec)

13. 创建一个普通用户并授权

mysql> grant all on *.* to user1 identified by '';
Query OK,  rows affected (0.01 sec)

all 表示所有的权限（读、写、查询、删除等等操作）， *.* 前面的 * 表示所有的数据库，后面的 * 表示所有的表，identified by 后面跟密码，用单引号括起来。这里的user1指的是localhost上的user1，如果是给网络上的其他机器上的某个用户授权则这样:

mysql> grant all on db1.* to 'user2'@'10.0.2.100' identified by '';
Query OK,  rows affected (0.01 sec)

用户和主机的IP之间有一个@，另外主机IP那里可以用%替代，表示所有主机，例如:

mysql> grant all on db1.* to 'user3'@'%' identified by '';
Query OK,  rows affected (0.00 sec)

MySQL数据库的备份与恢复

备份:

[root@winner ~]# mysqldump  -uroot -p'root' mysql >/tmp/mysql.sql
不是在mysql>环境

使用 mysqldump 命令备份数据库，-u 和 -p 两个选项使用方法和前面说的 mysql 同样，而后面的 “mysql” 指的是库名，然后重定向到一个文本文档里。备份完后，你可以查看 /tmp/mysql.sql 这个文件里的内容。

恢复和备份正好相反:

[root@localhost ~]# mysql -uroot -p'yourpassword' mysql </tmp/mysql.sql