1. 下載并安裝MySQL官方的 Yum Repository
（1）使用下面的命令就直接下載了安裝用的Yum Repository，大概25KB的樣子，然后就可以直接yum安裝了。
[root@yzl yzl /]# wget -i -c http://dev.mysql.com/get/mysql57-community-release-el7-10.noarch.rpm
[root@yzl yzl /]# yum -y install mysql57-community-release-el7-10.noarch.rpm
安裝完成后會(huì)有如下提示：
Running transaction
正在安裝 : mysql57-community-release-el7-10.noarch 1/1
驗(yàn)證中 : mysql57-community-release-el7-10.noarch 1/1
已安裝:
mysql57-community-release.noarch 0:el7-10
完畢！
(2)下面就是使用yum安裝MySQL了,這步可能會(huì)花些時(shí)間，安裝完成后就會(huì)覆蓋掉之前的mariadb。
[root@yzl yzl /]# yum -y install mysql-community-server
安裝成功后會(huì)有如下提示：
已安裝:
mysql-community-libs.x86_64 0:5.7.23-1.el7
mysql-community-libs-compat.x86_64 0:5.7.23-1.el7
mysql-community-server.x86_64 0:5.7.23-1.el7
作為依賴被安裝:
mysql-community-client.x86_64 0:5.7.23-1.el7
mysql-community-common.x86_64 0:5.7.23-1.el7
替代:
mariadb-libs.x86_64 1:5.5.56-2.el7
完畢！
2. MySQL數(shù)據(jù)庫(kù)設(shè)置
（1）首先啟動(dòng)MySQL
[root@yzl yzl /]# systemctl start mysqld.service
（2）查看MySQL運(yùn)行狀態(tài)，運(yùn)行狀態(tài)如圖：
[root@yzl yzl /]# systemctl status mysqld.service
● mysqld.service - MySQL Server
Loaded: loaded (/usr/lib/systemd/system/mysqld.service; enabled; vendor preset: disabled)
Active: active (running) since 五 2018-08-31 11:06:13 CST; 1min 19s ago
Docs: man:mysqld(8)
http://dev.mysql.com/doc/refman/en/using-systemd.html
Process: 6765 ExecStart=/usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid $MYSQLD_OPTS (code=exited, status=0/SUCCESS)
Process: 6678 ExecStartPre=/usr/bin/mysqld_pre_systemd (code=exited, status=0/SUCCESS)
Main PID: 6768 (mysqld)
CGroup: /system.slice/mysqld.service
└─6768 /usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid...
8月 31 11:05:51 yzl systemd[1]: Starting MySQL Server...
8月 31 11:06:13 yzl systemd[1]: Started MySQL Server.
（3）此時(shí)MySQL已經(jīng)開始正常運(yùn)行，不過要想進(jìn)入MySQL還得先找出此時(shí)root用戶的密碼，通過如下命令可以在日志文件中找出密碼：
[root@yzl yzl /]# grep "password" /var/log/mysqld.log
2018-08-31T03:06:07.947523Z 1 [Note] A temporary password is generated for root@localhost: 1!0dT>9qF2rR
初始密碼為：1!0dT>9qF2rR
（4）如下命令進(jìn)入數(shù)據(jù)庫(kù)：
[root@yzl yzl]# mysql -uroot -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 2
Server version: 5.7.23
Copyright (c) 2000, 2018, 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>
此時(shí)不能做任何事情，因?yàn)镸ySQL默認(rèn)必須修改密碼之后才能操作數(shù)據(jù)庫(kù)：
（5）修改密碼
mysql> ALTER USER 'root'@'localhost' IDENTIFIED BY 'root';
ERROR 1819 (HY000): Your password does not satisfy the current policy requirements
我們嘗試將密碼修改為root，發(fā)現(xiàn)報(bào)錯(cuò)，原因密碼過于簡(jiǎn)單。剛安裝的mysql的密碼默認(rèn)強(qiáng)度是最高的，如果想要設(shè)置簡(jiǎn)單的密碼就要修改validate_password_policy的值，
validate_password_policy有以下取值：
mysql> set global validate_password_policy=0; #設(shè)置安全級(jí)別
Query OK, 0 rows affected (0.00 sec)
mysql> set global validate_password_length=4;#默認(rèn)密碼長(zhǎng)度為8，可以設(shè)置為其它值，最小4位
Query OK, 0 rows affected (0.01 sec)
mysql> ALTER USER 'root'@'localhost' IDENTIFIED BY 'root';
Query OK, 0 rows affected (0.01 sec)
3.可視化工具的登錄授權(quán)：(如果授權(quán)不成功，請(qǐng)查看防火墻)
操作完成上面的，現(xiàn)在還不能用可視化的客戶端進(jìn)行連接，需要我們進(jìn)行授權(quán)：
mysql> grant all on *.* to root@'%' identified by 'root';
Query OK, 0 rows affected, 1 warning (0.00 sec)
