CentOS安装MySQL问题汇总

遇到的错误

ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: NO) denied for user 'root'@'localhost' (using password: NO)

描述：刚安装完MySQL，第一次登陆。

[wangyang@CentOS ~]$ mysql -u root -p
Enter password: #我记得root初始是没密码的，这句直接回车
ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: NO) denied for user 'root'@'localhost' (using password: NO)

然后我就直接尝试修改MySQL的root密码：

[wangyang@CentOS ~]$ mysqladmin -u root -p password 123456
Enter password: 
mysqladmin: connect to server at 'localhost' failed
error: 'Access denied for user 'root'@'localhost' (using password: YES)'

问题是什么我没弄清楚，解决方案如下：

[root@CentOS ~]# service mysql stop
[root@CentOS ~]# mysqld_safe --user=mysql --skip-grant-tables --skip-networking & 
[wangyang@CentOS ~]$ mysql -u root mysql 
mysql> UPDATE user SET Password=PASSWORD(’newpassword’) where USER=’root’; #newpassword为root新密码
mysql> FLUSH PRIVILEGES;
mysql> quit
[root@CentOS ~]# service mysql start
[wangyang@CentOS ~]$ mysql -u root -p
Enter password: #输入新密码，OK

You must SET PASSWORD before executing this statement

描述：参考前文利用安全模式成功登陆，然后修改密码，等于给MySql设置了密码。登陆进去后，想创建一个数据库测试下。得到的结果却是：

ERROR 1820 (HY000): You must SET PASSWORD before executing this statement

解决方法：

mysql> create database localtest;
ERROR 1820 (HY000): You must SET PASSWORD before executing this statement
mysql> SET PASSWORD = PASSWORD('123456');
Query OK, 0 rows affected (0.03 sec)

mysql> create database yan1;
Query OK, 1 row affected (0.00 sec)

不懂为什么再设置一遍密码。