第一次打开mysqlshi报错“Accerss denied for user 'root'@local

可以依次执行下面几步：

1.Start the MySQL server instance or daemon with the –skip-grant-tables option (security setting).

$ mysqld --skip-grant-tables

2.Execute these statements.

$ mysql -u root mysql

$mysql> UPDATE user SET Password=PASSWORD('my_password') where USER='root';

$mysql> FLUSH PRIVILEGES;

3.Finally, restart the instance/daemon without the –skip-grant-tables option.

$ /etc/init.d/mysql restart

然后就可以了 stackoverflow的链接：http://superuser.com/questions/603026/mysql-how-to-fix-access-denied-for-user-rootlocalhost

如果上面还不行可能是没关闭mysql服务：

1. mysqld –skip-grant-tables

2. mysql -u root

3. use mysql;

4. update user set password=PASSWORD(“NEW-ROOT-PASSWORD”) where User=’root’;

5. flush privileges;

6. quit

然后，关闭mysql 服务

5.7 mysql的密码字段改名了

“password” => "authentication_string"