方法一：
1、使用空的初始密碼登錄mysql賬號：
mysql-uroot -p
2、修改root密碼：
SETPASSWORD = PASSWORD('123456');
方法二：
1、使用空的初始密碼登錄mysql賬號：
mysql-uroot -p
2、修改root密碼：
mysqladmin -u root password '123456'
方法三：
1、使用空的初始密碼登錄mysql賬號：
mysql-uroot -p
2、修改root密碼：
mysql> update user set Password=password("123456") where User='root';
Query OK, 4 rows affected (0.01 sec)
Rows matched: 4 Changed: 4 Warnings: 0
mysql> flush privileges;
Query OK, 0 rows affected (0.04 sec)
mysql> select Host,User,password from user where user='root';
+-----------------------+------+-------------------------------------------+
| Host | User | password |
+-----------------------+------+-------------------------------------------+
| localhost | root | *5626ED34B75C6C508BA2A3D0A4F6E4C58823138C |
| localhost.localdomain | root | *5626ED34B75C6C508BA2A3D0A4F6E4C58823138C |
| 127.0.0.1 | root | *5626ED34B75C6C508BA2A3D0A4F6E4C58823138C |
| ::1 | root | *5626ED34B75C6C508BA2A3D0A4F6E4C58823138C |
+-----------------------+------+-------------------------------------------+
4 rows in set (0.00 sec)
