1.安装
sudo apt update sudo apt install mysql-server
安装后进不去
重启mysql服务后成功进入
2.重启mysql服务后登录（不需要密码）
service mysql restar
mysql -h localhost -u root
3.修改密码（第一次不修改了再退出 之后就登不上了）
（1）第一次尝试
update mysql.user set password=password('root') where user='root' ;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '('root') where user='root'' at line 1
mysql> update mysql.user set password=password('root') where user='root' ;
然后试一下
select password from user;
ERROR 1054 (42S22): Unknown column 'password' in 'field list'
原因是password字段名改为 authentication_string 了
（2）第二次尝试
update mysql.user set authentication_string=password('root') where user='root' ;
ERROR 1064 (42000) You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ‘password(‘123456’)’ at line 1
（3）又重新搜了一下，第三次尝试
ALTER USER 'root'@'localhost' IDENTIFIED BY '123456';
或者
SET PASSWORD = '123456'
4.退出后快乐重新输入密码进入
