1、关闭mysql服务

service mysqld stop

2、清理datadir(本例中指定的是/var/lib/mysql)指定的目录下的文件，将该目录下的所有文件删除或移动至其他位置

cd /var/lib/mysql

mv * /opt/mysql_back/

3、初始化实例

/usr/local/mysql/bin/mysqld --initialize --user=mysql

4、重复安装过程中创建用户的步骤，修改默认密码，重新创建数据库和用户即可

/usr/local/mysql/bin/mysql -uroot -p

mysql> set password = 'mysqltest123';

mysql>create database ecology;

mysql> create user ecology identified with mysql_native_password by 'ecology123';

mysql> grant all privileges on *.* to 'ecology'@'%';

mysql> flush privileges;