1.卸载
完全删除MySQL 5.7，没有安装的朋友可跳过此阶段
1. 1 删除MySQL的相关文件及其子目录
sudo apt-get remove mysql-*
1.2 清理残留的数据
dpkg -l |grep ^rc|awk '{print $2}' |sudo xargs dpkg -P
2. 安装
# 安装mysql服务sudo apt-get install mysql-server# 安装客户端sudo apt install mysql-client# 安装依赖sudo apt install libmysqlclient-dev# 检查状态sudo netstat -tap | grep mysql
3. 配置root密码
注意：MySQL5.7安装时不会提示配置密码和用户名，可通过输入mysql直接进入，原因：root的plugin被修改成了auth_socket，用密码登陆的plugin应该是mysql_native_password，直接用root权限登录就不用密码,修改root密码和登录验证方式
3.1查看mysql初始的用户、密码及登录验证方式
root> mysql
Welcome to the MySQL monitor. Commands end with ; or \g.
......
mysql> select user, authentication_string,plugin from user;
+------------------+-------------------------------------------+-----------------------+
| user | authentication_string | plugin |
+------------------+-------------------------------------------+-----------------------+
| root | | auth_socket |
| mysql.session | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE | mysql_native_password |
| mysql.sys | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE | mysql_native_password |
| debian-sys-maint | *C58EEC8342F164C89DFA6128785719DE1AC73DAE | mysql_native_password |
+------------------+-------------------------------------------+-----------------------+
4 rows in set (0.00 sec)
如上可知mysql初始的root用户没有密码且plugin为auth_socket这种方式
3.2设置密码和登录验证方式
mysql> update mysql.user set authentication_string=PASSWORD('123456'), plugin='mysql_native_password' where user='root';
mysql> flush privileges;
mysql> exit
Bye
# exit
$ sudo /etc/init.d/mysql restart
$ mysql -uroot -pEnter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 2
Server version: 5.7.22-0ubuntu18.04.1 (Ubuntu)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>
4. 配置MySQL远程登录
# 修改配置文件，注释掉bind-address = 127.0.0.1
$ sudo vi /etc/mysql/mysql.conf.d/mysqld.cnf# 保存退出，然后进入mysql服务，执行授权命令：
$ mysql -uroot -pmysql> grant all on *.* to root@'%' identified by '123456' with grant option;
Query OK, 0 rows affected, 1 warning (0.00 sec)mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)mysql> exit
Bye
$ sudo /etc/init.d/mysql restart