首次在centos下安装MySQL，客户端链接mysql时报错：

mysql版本：5.7.13 首次在centos下安装MySQL，客户端链接mysql时报错： [plain] view plain copy 在CODE上查看代码片派生到个人代码片 [root@localhost opt]# /usr/bin/mysql -u root
ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: NO)

【解决】： 一、找到密码 [plain] view plain copy 在CODE上查看代码片派生到个人代码片 [root@localhost opt]# cat /var/log/mysqld.log | grep password
2016-07-16T05:01:47.771362Z 1 [Note] A temporary password is generated for root@localhost: q.)aq!YaH6y-
2016-07-16T05:02:32.000199Z 2 [Note] Access denied for user 'root'@'localhost' (using password: NO)
2016-07-16T05:02:39.063852Z 3 [Note] Access denied for user 'root'@'localhost' (using password: NO)

二、从新链接mysql： [plain] view plain copy 在CODE上查看代码片派生到个人代码片 [root@zzs171 opt]# /usr/bin/mysql -u root -p
Enter password:
输入上面找到的密码，便可进入mysql客户端链接。

三、修改mysql的root的密码： 进入mysql客户端以后，show databases; 会提醒先修改密码： [plain] view plain copy 在CODE上查看代码片派生到个人代码片 mysql> show databases;
ERROR 1820 (HY000): You must reset your password using ALTER USER statement before executing this statement.
设置密码，如下两种方式都可： [plain] view plain copy 在CODE上查看代码片派生到个人代码片 SET PASSWORD FOR 'root'@'localhost' = PASSWORD('Mysqlpassw0rd.');

alter user 'root'@'localhost' identified by 'Mysqlpassw0rd.';

OK，至此设置成功。注意mysql有密码复杂度的限制。密码太简单会提示： [plain] view plain copy 在CODE上查看代码片派生到个人代码片 mysql> SET PASSWORD FOR 'root'@'localhost' = PASSWORD('123');
ERROR 1819 (HY000): Your password does not satisfy the current policy requirements