【若泽大数据实战第六天】MySQL的一些常用命令

1、登录 mysql
# su - mysqladmin
[mysqladmin@hadoop-01 ~]$ mysql -uroot -p （不要输入密码，否则history可以查看的到密码信息）
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 1
Server version: 5.6.23-log MySQL Community Server (GPL)


Copyright (c) 2000, 2015, 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.




2、查看数据库信息


mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| db01               |
| mysql              |
| performance_schema |
| test               |
+--------------------+
5 rows in set (0.02 sec)


3、切换db


mysql> use mysql
Database changed


4、查看当前mysql的用户，密码，机器ip地址（5.6版）


mysql> select user,password,host from user;
+------+-------------------------------------------+-----------+
| user | password                                  | host      |
+------+-------------------------------------------+-----------+
| root | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 | localhost |
| root | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 | hadoop-01 |
| root | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 | 127.0.0.1 |


这里的host代表我这个机器可以通过哪个用户来访问


如果有一台机器在国外要访问我这个mysql我应该修改哪些东西，让他来访问我这台mysql机器


答：
mysql> update mysql.user set Host='%' where Host='hadoop-01'; （百分号可以修改为客户的ip地址）
mysql> flush privileges;


5、mysql重新部署
[mysqladmin@hadoop-01 ~]$ cd /usr/local/mysql
drwxr-xr-x.  2 mysqladmin dba   4096 May 12 08:32 arch
drwxrwxr-x.  5 mysqladmin dba   4096 May 12 08:44 data


1. rm -rf /usr/local/mysql/arch/*  
   rm -rf  /usr/local/mysql/data/*
2. scripts/mysql_install_db  --user=mysqladmin --basedir=/usr/local/mysql --datadir=/usr/local/mysql/data 


6、查看mysql数据库下有多少张表


mysql> show tables;
+---------------------------+
| Tables_in_mysql           |
+---------------------------+
| columns_priv              |
| db                        |
| event                     |
| func                      |
| general_log               |
| help_category             |
| help_keyword              |
| help_relation             |
| help_topic                |
| innodb_index_stats        |
| innodb_table_stats        |
| ndb_binlog_index          |
| plugin                    |
| proc                      |
| procs_priv                |
| proxies_priv              |
| servers                   |
| slave_master_info         |
| slave_relay_log_info      |
| slave_worker_info         |
| slow_log                  |
| tables_priv               |
| time_zone                 |
| time_zone_leap_second     |
| time_zone_name            |
| time_zone_transition      |
| time_zone_transition_type |
| user                      |
+---------------------------+
28 rows in set (0.00 sec)


7、查看user底下有多少个字段
mysql> desc user;
+------------------------+-----------------------------------+------+-----+-----------------------+-------+
| Field                  | Type                              | Null | Key | Default               | Extra |
+------------------------+-----------------------------------+------+-----+-----------------------+-------+
| Host                   | char(60)                          | NO   | PRI |                       |       |
| User                   | char(16)                          | NO   | PRI |                       |       |
| Password               | char(41)                          | NO   |     |                       |       |
| 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                     |       |
| Reload_priv            | enum('N','Y')                     | NO   |     | N                     |       |
| Shutdown_priv          | enum('N','Y')                     | NO   |     | N                     |       |
| Process_priv           | enum('N','Y')                     | NO   |     | N                     |       |
| File_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                     |       |
| Show_db_priv           | enum('N','Y')                     | NO   |     | N                     |       |
| Super_priv             | enum('N','Y')                     | NO   |     | N                     |       |
| Create_tmp_table_priv  | enum('N','Y')                     | NO   |     | N                     |       |
| Lock_tables_priv       | enum('N','Y')                     | NO   |     | N                     |       |
| Execute_priv           | enum('N','Y')                     | NO   |     | N                     |       |
| Repl_slave_priv        | enum('N','Y')                     | NO   |     | N                     |       |
| Repl_client_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                     |       |
| Create_user_priv       | enum('N','Y')                     | NO   |     | N                     |       |
| Event_priv             | enum('N','Y')                     | NO   |     | N                     |       |
| Trigger_priv           | enum('N','Y')                     | NO   |     | N                     |       |
| Create_tablespace_priv | enum('N','Y')                     | NO   |     | N                     |       |
| ssl_type               | enum('','ANY','X509','SPECIFIED') | NO   |     |                       |       |
| ssl_cipher             | blob                              | NO   |     | NULL                  |       |
| x509_issuer            | blob                              | NO   |     | NULL                  |       |
| x509_subject           | blob                              | NO   |     | NULL                  |       |
| max_questions          | int(11) unsigned                  | NO   |     | 0                     |       |
| max_updates            | int(11) unsigned                  | NO   |     | 0                     |       |
| max_connections        | int(11) unsigned                  | NO   |     | 0                     |       |
| max_user_connections   | int(11) unsigned                  | NO   |     | 0                     |       |
| plugin                 | char(64)                          | YES  |     | mysql_native_password |       |
| authentication_string  | text                              | YES  |     | NULL                  |       |
| password_expired       | enum('N','Y')                     | NO   |     | N                     |       |
+------------------------+-----------------------------------+------+-----+-----------------------+-------+


8、查看创建user表的创建语法


mysql> show create table user;


| user  | CREATE TABLE `user` (
  `Host` char(60) COLLATE utf8_bin NOT NULL DEFAULT '',
  `User` char(16) COLLATE utf8_bin NOT NULL DEFAULT '',
  `Password` char(41) CHARACTER SET latin1 COLLATE latin1_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',
  `Reload_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
  `Shutdown_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
  `Process_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
  `File_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',
  `Show_db_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
  `Super_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',
  `Execute_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
  `Repl_slave_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
  `Repl_client_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',
  `Create_user_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
  `Event_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
  `Trigger_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
  `Create_tablespace_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
  `ssl_type` enum('','ANY','X509','SPECIFIED') CHARACTER SET utf8 NOT NULL DEFAULT '',
  `ssl_cipher` blob NOT NULL,
  `x509_issuer` blob NOT NULL,
  `x509_subject` blob NOT NULL,
  `max_questions` int(11) unsigned NOT NULL DEFAULT '0',
  `max_updates` int(11) unsigned NOT NULL DEFAULT '0',
  `max_connections` int(11) unsigned NOT NULL DEFAULT '0',
  `max_user_connections` int(11) unsigned NOT NULL DEFAULT '0',
  `plugin` char(64) COLLATE utf8_bin DEFAULT 'mysql_native_password',
  `authentication_string` text COLLATE utf8_bin,
  `password_expired` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
  PRIMARY KEY (`Host`,`User`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8 COLLATE=utf8_bin COMMENT='Users and global privileges' |




9、更改用户密码
mysql> update mysql.user set password=password('123456') where user='root';
mysql> flush privileges;
Query OK, 4 rows affected (0.03 sec)




10、如果有空的账号如何删除
mysql> select user,password,host from user;
+------+-------------------------------------------+-----------+
| user | password                                  | host      |
+------+-------------------------------------------+-----------+
| root | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 | localhost |
| root | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 | hadoop-01 |
| root | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 | 127.0.0.1 |
|      |                                           | localhost |
|      |                                           | hadoop-01 |


mysql> delete from mysql.user where user=''
Query OK, 2 rows affected (0.03 sec)


结果：
+------+-------------------------------------------+-----------+
| user | password                                  | host      |
+------+-------------------------------------------+-----------+
| root | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 | localhost |
| root | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 | hadoop-01 |
| root | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 | 127.0.0.1 |


11、访问其他机器的mysql
[mysqladmin@hadoop-01 ~]$ mysql -uroot -p123456 -h192.168.137.251 mysql(哪个数据库)


12、创建新的DB和用户
创建一个用户只对db01有权限
mysql> create database db01;
mysql> grant all privileges on db.* to db01@'%' identified by '123456';


13、查看当前有多少用户链接进数据库：
mysql> show processlist;
+----+------+---------------------+-------+---------+------+-------+------------------+
| Id | User | Host                | db    | Command | Time | State | Info             |
+----+------+---------------------+-------+---------+------+-------+------------------+
|  2 | root | localhost           | mysql | Query   |    0 | init  | show processlist |
|  6 | root | 192.168.137.1:56219 | mysql | Sleep   | 1110 |       | NULL             |
|  7 | root | 192.168.137.1:56220 | mysql | Sleep   | 1110 |       | NULL             |
|  9 | root | 192.168.137.1:57984 | db01  | Sleep   |  302 |       | NULL             |
| 10 | root | 192.168.137.1:57987 | db01  | Sleep   |  302 |       | NULL             |
| 11 | root | 192.168.137.1:57992 | db01  | Sleep   |  300 |       | NULL             |
| 12 | root | 192.168.137.1:58067 | mysql | Sleep   |  242 |       | NULL             |
+----+------+---------------------+-------+---------+------+-------+------------------+
把 id 9的连接杀掉
mysql> kill 9;

Query OK, 0 rows affected (0.00 sec)

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