忘记root密码
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1. 首先关闭mysql，然后使用不验证权限的方式启动：
mysql> mysqld_safe --skip-grant-tables &
2. 直接shell中输入：mysql，进入后对root授权：
mysql> update mysql.user set password=PASSWORD('root') where User='root';
mysql> flush privileges;
mysql> grant all privileges on *.* to 'root'@'%' identified by 'root';
mysql> alter user 'root'@'localhost' identified by '123456';
mysql> update user set password=password("123456") where user="root";
mysql>update mysql.user set authentication_string=password('123456') where user='root' and Host ='localhost';
mysql>flush privileg