1、打开终端，输入命令：cd /usr/local/mysql/bin
2、mysql -uroot -p，用这条命令登陆时报错信息：
报错：Enter password: ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: YES)
3、打开终端输入：sudo mysqld_safe --skip-grant-tables
输出 Password: Logging to '/usr/local/mysql/data/localhost.err'. 2018-10-10T03:21:40.6NZ mysqld_safe Starting mysqld daemon with databases from /usr/local/mysql/data
4、打开一个新的终端，输入：mysql -u root ，会看到以下输出。
Welcome to the MySQL monitor. Commands end with ; or g. Your MySQL connection id is 16 Server version: 5.7.23 MySQL Community Server (GPL) 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>
5、终端输入 use mysql显示如下
Reading table information for completion of table and column names You can turn off this feature to get a quicker startup with -A Database changed
6、修改密码：UPDATE mysql.user SET authentication_string=PASSWORD('你的密码') WHERE User='root';
Query OK, 1 row affected, 1 warning (0.01 sec)
Rows matched: 1 Changed: 1 Warnings: 1