CentoS7 and MySql 5.7下载安装

一：安装

#下载官方yum源
[root@localhost ~]# wget -i -c http://dev.mysql.com/get/mysql57-community-release-el7-10.noarch.rpm
#安装yum 源
[root@localhost ~]# yum -y install mysql57-community-release-el7-10.noarch.rpm
# 安装mysql
[root@localhost ~]# yum -y install mysql-community-server

第二：启动

[root@localhost ~]# systemctl start mysqld.service  #开启sql
[root@localhost ~]# systemctl status mysqld.service  #查看状态

[root@localhost ~]# systemctl restart mysqld.service #重启

第三：查看

ps aux | grep 'mysqld'     查看进程
netstat -an | grep '3306'  查看端口

第四：查看密码

[root@localhost ~]# grep "password" /var/log/mysqld.log   #查看密码

 第五：登陆

[root@localhost ~]# mysql -uroot -pkyJt9dy#xsnn

第六：修改初始密码

mysql> ALTER USER 'root'@'localhost' IDENTIFIED BY '[email protected]';  # 修改成：[email protected]

------------------------------------------------------------------------------------

#降低密码难度(与validate_password_policy 值有关)

mysql> SHOW VARIABLES LIKE 'validate_password%';
+--------------------------------------+-------+
| Variable_name | Value |
+--------------------------------------+-------+
| validate_password_check_user_name | OFF |
| validate_password_dictionary_file | |
| validate_password_length | 4 |
| validate_password_mixed_case_count | 1 |
| validate_password_number_count | 1 |
| validate_password_policy | LOW |
| validate_password_special_char_count | 1 |
+--------------------------------------+-------+

mysql> set global validate_password_policy=0;
mysql> set global validate_password_length=1;

------------------------------------------------------------
mysql> ALTER USER 'root'@'localhost' IDENTIFIED BY '123456';  # 修改成：123456

 第七：忘记密码

一：
[root@localhost ~]# vim /etc/my.cnf
[mysqld]
skip-grant-tables=1

二：重启
[root@localhost ~]# systemctl restart mysqld.service

三：无需密码登陆
[root@localhost ~]# mysql -uroot

四：修改密码
mysql> use mysql;  #进入数据库
# 修改密码
mysql> update user set authentication_string = password('123456'), password_last_changed =now() where user = 'root'

五：
将/etc/my.conf里的 skip-grant-tables=1 去掉并保存重启