mysql（MySQL客户端连接工具）

在MySQL提供的工具中，DBA使用最频繁的莫过于mysql。这里的mysql不是指MySQL服务，也不是mysql数据库，而是连接数据库的客户端工具。类似于Oracle的sqlplus。

语法： 
mysql [options][database]

options是mysql的可用选项，一次可以写一个或者多个，甚至可以不写。database表示连接的数据库，一次只能写一个或者不写，如果不写，在登录数据库后还需要使用use dbname选择数据库。

mysql的选项通常有两种表达方式：

1. -+选项单词的缩写+选项值**；
2. --+选项的完整单词+=+选项的实际值；

例如:
mysql -uroot -ppassword 
mysql --user=root --password=password 

1.连接选项

-u,--user=name 指定连接的用户名 
-p,--password=password 指定连接密码 
-h,--host=name 指定服务器IP或域名 
-P,--port=3308 指定连接端口

在默认情况下，如果这些选项都不写，mysql将会使用'用户'@'localhost'和空密码连接本机的3306端口。空用户会在mysql安装完毕后自动生成，这也就是仅使用mysql命令就能连到数据库的原因。

如果客户端和服务器在用一台机器上，通常不需要指定-h选项，否则需要指定mysql服务所在的IP或主机名。如果不指定端口，默认连接到3306端口。示例如下：　

# mysql -h 10.10.200.202 -uroot -p
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or g.
Your MySQL connection id is 75520
Server version: 5.6.28 Source distribution
Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or 'h' for help. Type 'c' to clear the current input statement.
mysql> 

2.指定客户端字符集

--default-character-set=charset-name为服务器的字符集选项。该选项可以配置在my.cnf的[mysqld]组中，同样也可以作为客户端字符集选项，也可以配置在[mysql]组中。在使用mysql命令登录数据库时，使用--default-character-set选项可以指定客户端的字符集。例如，如果未使用--default-character-set选项登录数据库时：

# mysql -h 10.10.200.202 -uroot -p
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or g.
Your MySQL connection id is 75520
Server version: 5.6.28 Source distribution
Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or 'h' for help. Type 'c' to clear the current input statement.
mysql> show variables like 'chara%';
+--------------------------+-----------------------------------------+
| Variable_name            | Value                                   |
+--------------------------+-----------------------------------------+
| character_set_client     | latin1                                  |
| character_set_connection | latin1                                  |
| character_set_database   | utf8                                    |
| character_set_filesystem | binary                                  |
| character_set_results    | latin1                                  |
| character_set_server     | utf8                                    |
| character_set_system     | utf8                                    |
| character_sets_dir       | /usr/local/mysql-5.6.28/share/charsets/ |
+--------------------------+-----------------------------------------+

当使用--default-character-set选项登录数据库时：

# mysql -h 10.10.200.202 -uroot -p --default-character-set=utf8
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or g.
Your MySQL connection id is 75542
Server version: 5.6.28 Source distribution
Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or 'h' for help. Type 'c' to clear the current input statement.
mysql> show variables like 'chara%';
+--------------------------+-----------------------------------------+
| Variable_name            | Value                                   |
+--------------------------+-----------------------------------------+
| character_set_client     | utf8                                    |
| character_set_connection | utf8                                    |
| character_set_database   | utf8                                    |
| character_set_filesystem | binary                                  |
| character_set_results    | utf8                                    |
| character_set_server     | utf8                                    |
| character_set_system     | utf8                                    |
| character_sets_dir       | /usr/local/mysql-5.6.28/share/charsets/ |
+--------------------------+-----------------------------------------+
8 rows in set (0.01 sec)

3.执行选项

-e,--execute=name 执行sql语句并退出 
此选项可以直接在客户端执行SQL语句，而不用连接到MySQL数据库后再执行，对于一些脚本的执行，使用此法较为便利。可以使用此种方法连续执行多条SQL语句，语句之间用分号(;)分隔例如：

# mysql -uroot -p mysql -e "select host,user from user"
Enter password: 
+--------------------+--------+
| host               | user   |
+--------------------+--------+
| 10.10.200.201      | root   |
| 10.10.200.201      | zabbix |
| 127.0.0.1          | root   |
| ::1                | root   |
| localhost          |        |
| localhost          | root   |
| localhost          | zabbix |
| tcxx-ops-mysql-202 |        |
| tcxx-ops-mysql-202 | root   |
+--------------------+--------+

4.格式化选项

-E,--vertical 将输出按字段顺序垂直显示 
-s,--silent 去掉SQL输出结果中的线条框

# mysql -uroot -p mysql -e "select host,user from user" -E
Enter password: 
*************************** 1. row ***************************
host: 127.0.0.1
user: root
*************************** 2. row ***************************
host: ::1
user: root
*************************** 3. row ***************************
host: localhost
user: 
*************************** 4. row ***************************
host: localhost
user: root
*************************** 5. row ***************************
host: test-server
user: 
*************************** 6. row ***************************
host: test-server
user: root