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：
-+选项单词的缩写+选项值**；--+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
