概述

有朋友問怎么去看連接MySQL數據庫有哪些用戶及對應的IP地址等等信息，所以順便整理了下這塊內容，下面是涉及的一些命令。

1、查看當前連接到數據庫的用戶和Host

## 查看當前連接到數據庫的用戶和Host ##
SELECT DISTINCT USER,HOST FROM `information_schema`.`PROCESSLIST` P WHERE P.USER NOT IN('root','repl','system user');

2、查看每個host的當前連接數和總連接數

SELECT * FROM performance_schema.hosts;

PS1: 系統表performance_schema.hosts在MySQL 5.6.3版本中引入，用來保存MySQL服務器啟動后的連接情況。

3、按照登錄用戶+登錄服務器查看登錄信息

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、按照登錄用戶+數據庫+登錄服務器查看登錄信息

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);