mysql5.7修改密码

　　为了提高安全性，mysql5.7中 user 表的 password 被 authentication_string 字段所取代，下面简绍几种修改root密码的方法（其他用户也大同小异）。

推荐顺序：

法一：

mysql> alter user 'root'@'localhost' identified by 'cy7m0ypu8CpLFperzI45';

法二：

mysql> set password for 'root'@'localhost'=password('cy7m0ypu8CpLFperzI45');

法三：

mysql> update mysql.user set authentication_string=password('cy7m0ypu8CpLFperzI45') where user='root' and Host = 'localhost';

-- 记得最后要刷新权限
mysql> flush privileges;

具体示例：

[mysql@db134 application]$ /data/mysql/application/mysql/bin/mysql -uroot -p -h localhost --socket=/data/mysql/percona_server_new/run/mysql.sock
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 3
Server version: 5.7.17-13-log

Copyright (c) 2009-2016 Percona LLC and/or its affiliates
Copyright (c) 2000, 2016, 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> set global validate_password_policy=LOW;
Query OK, 0 rows affected (0.00 sec)

mysql> set password for 'root'@'localhost'=password('cy7m0ypu8CpLFperzI45');
Query OK, 0 rows affected, 1 warning (0.08 sec)

mysql> alter user 'root'@'localhost' identified by 'cy7m0ypu8CpLFperzI45';
Query OK, 0 rows affected (0.01 sec)

mysql> update mysql.user set authentication_string=password('cy7m0ypu8CpLFperzI45') where user='root' and Host = 'localhost';
Query OK, 0 rows affected, 1 warning (0.05 sec)
Rows matched: 1  Changed: 0  Warnings: 1

mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)

-- 验证登录
[mysql@db134 application]$ /data/mysql/application/mysql/bin/mysql -uroot -p -h localhost --socket=/data/mysql/percona_server_new/run/mysql.sock 
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 4
Server version: 5.7.17-13-log Percona Server (GPL), Release 13, Revision fd33d43

Copyright (c) 2009-2016 Percona LLC and/or its affiliates
Copyright (c) 2000, 2016, 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> exit
Bye
[mysql@db134 application]$

修改其他用户示例：

mysql> create database db_test;
Query OK, 1 row affected (0.35 sec)

mysql> create user 'test_u'@'%' identified by 'kkSWhEpMVZ1xfaebJsRS';
Query OK, 0 rows affected (0.06 sec)

mysql> grant select,insert,delete,update on db_test.* to 'test_u'@'%' ;
Query OK, 0 rows affected (0.00 sec)

-- 测试新建的账号
[root@db134 ~]# mysql -h 192.168.142.134 -utest_u -p'kkSWhEpMVZ1xfaebJsRS'
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 7
Server version: 5.7.17-13-log Percona Server (GPL), Release 13, Revision fd33d43

Copyright (c) 2009-2016 Percona LLC and/or its affiliates
Copyright (c) 2000, 2016, 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> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| db_test            |
+--------------------+
2 rows in set (0.00 sec)

-- 假设该用户忘记密码
-- 用管理员账号登录操作
mysql> select user,host,authentication_string from mysql.user;
+-----------+-----------+-------------------------------------------+
| user      | host      | authentication_string                     |
+-----------+-----------+-------------------------------------------+
| root      | localhost | *9EF2DB3EB868F2BF2AF1F8DD00185B23390E20A3 |
| mysql.sys | localhost | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE |
| test_u    | %         | *240FADB0A594DB97220A0F354CF891C0EF9F00D4 |
+-----------+-----------+-------------------------------------------+
3 rows in set (0.00 sec)
mysql> alter user 'test_u'@'%' identified by 'kkSWhEpMVZ1xfaebJsHK';
Query OK, 0 rows affected (0.01 sec)

-- 用新密码验证登录
[root@db134 ~]# mysql -h 192.168.142.134 -utest_u -p'kkSWhEpMVZ1xfaebJsHK'
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 10
Server version: 5.7.17-13-log Percona Server (GPL), Release 13, Revision fd33d43

Copyright (c) 2009-2016 Percona LLC and/or its affiliates
Copyright (c) 2000, 2016, 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> exit
Bye
[root@db134 ~]# 

-- 其他两种方法均可
mysql> set password for 'test_u'@'%'=password('kkSWhEpMVZ1xfaebJsXY');
Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql>  update mysql.user set authentication_string=password('kkSWhEpMVZ1xfaebJsHG') where user='test_u' and Host = '%';  -- 这个操作，必须执行flush privileges;才能生效  
Query OK, 1 row affected, 1 warning (0.08 sec)
Rows matched: 1  Changed: 1  Warnings: 1

mysql> 
mysql> flush privileges;
Query OK, 0 rows affected (0.01 sec)