概述

有朋友问怎么去看连接MySQL数据库有哪些用户及对应的IP地址等等信息，所以顺便整理了下这块内容，下面是涉及的一些命令。

1、查看当前连接到数据库的用户和Host

## 查看当前连接到数据库的用户和Host ##
SELECT DISTINCT USER,HOST FROM `information_schema`.`PROCESSLIST` P WHERE P.USER NOT IN('root','repl','system user');

2、查看每个host的当前连接数和总连接数

SELECT * FROM performance_schema.hosts;

PS1: 系统表performance_schema.hosts在MySQL 5.6.3版本中引入，用来保存MySQL服务器启动后的连接情况。

3、按照登录用户+登录服务器查看登录信息

SELECT USER AS
 login_user,
 LEFT ( HOST, POSITION( ':' IN HOST ) - 1 ) AS login_ip,
 count( 1 ) AS login_count 
FROM
 `information_schema`.`PROCESSLIST` P 
WHERE
 P.USER NOT IN ( 'root', 'repl', 'system user' ) 
GROUP BY
 USER,
 LEFT ( HOST, POSITION( ':' IN HOST ) - 1 );

4、按照登录用户+数据库+登录服务器查看登录信息

SELECT
DB as database_name,
USER as login_user,
LEFT(HOST,POSITION(':' IN HOST)-1) AS login_ip,
count(1) as login_count
FROM `information_schema`.`PROCESSLIST` P
WHERE P.USER NOT IN('root','repl','system user')
GROUP BY DB,USER,LEFT(HOST,POSITION(':' IN HOST)-1);