MYSQL密碼相關設置方法（以5.1版本爲例）

1、mysql設置密碼的幾種方法
新安裝的mysql數據庫是沒有密碼的
[root@localhost ~]# mysql -u root -p
Enter password: ###此處爲空，直接回車
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 6
Server version: 5.1.73 Source distribution
Copyright (c) 2000, 2013, 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>

設置方法：
一、在用root帳號進入mysql後設置密碼
mysql> set password=password('123456'); ###123456爲密碼
Query OK, 0 rows affected (0.00 sec)

mysql> set password=password(''); ###清除密碼，如今爲空
Query OK, 0 rows affected (0.00 sec)

mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec) ###刷新，使修改當即生效

二、在mysql外部（操做系統）設置密碼
[root@localhost ~]# mysqladmin -u root password '123456' ###此命令是在/usr/bin/mysqladmin中
[root@localhost ~]# whereis mysqladmin
mysqladmin: /usr/bin/mysqladmin

三、登錄數據庫，切換到數據庫後
mysql> use mysql;
Database changed

mysql> UPDATE user SET password=PASSWORD("123456") WHERE user='root'; #大小寫可忽略，123456即爲設置的密碼
Query OK, 3 rows affected (0.00 sec)
Rows matched: 3 Changed: 3 Warnings: 0

mysql> flush privileges;

2、修改密碼
一、進入數據庫以後修改密碼
mysql> use mysql;

mysql> update user set password = password('abcdef') where user = 'root'; ###abcdef爲新密碼

mysql> flush privileges;

二、在mysql外部（操做系統）修改密碼
mysqladmin -u root password oldpass 「newpass」 、

3、root密碼丟失，恢復root密碼
一、關閉mysql
[root@localhost ~]# service mysqld stop
中止 mysqld： [肯定]

二、跳過mysql權限後臺啓動
[root@localhost ~]# /usr/bin/mysqld_safe --user=mysql --skip-grant-tables &
[1] 31755
[root@localhost ~]# 180406 19:52:45 mysqld_safe Logging to '/var/log/mysqld.log'.
180406 19:52:45 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql

三、執行mysql命令，進入數據庫
[root@localhost ~]# mysql
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 1
Server version: 5.1.73 Source distribution

Copyright (c) 2000, 2013, 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>

四、修改密碼
mysql> use mysql;

mysql> update user set password=password('123456') where user='root';
Query OK, 2 rows affected (0.00 sec)
Rows matched: 3 Changed: 2 Warnings: 0

五、中止mysql,再以正常方式啓動[root@localhost ~]# service mysqld stop180406 19:57:47 mysqld_safe mysqld from pid file /var/run/mysqld/mysqld.pid ended中止 mysqld： [肯定][1]+ Done /usr/bin/mysqld_safe --user=mysql --skip-grant-tables[root@localhost ~]# service mysqld start正在啓動 mysqld： [肯定][root@localhost ~]#