yum安装mysql步骤及报错ERROR 1045 (28000)

1.centos 系统中使用yum工具安装 mysql.

[root@localhost ~]#yum install -y mysql

2.yum install -y mysql后，启动mysql报错如下：
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)解决办法：缺少组件，安装mysql-server包。
3.安装组件mysql-server

[root@localhost ~]#yum install -y mysql-server

4.启动mysql

[root@localhost ~]#service mysqld start

5.使用mysql报错

[root@localhost ~]# mysql
ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: NO)

6.报错解决办法

（1）service mysqld stop

（2）/usr/bin/mysqld_safe --skip-grant-tables

（3）另外开个SSH连接
[root@localhost ~]# mysql
mysql> GRANT ALL PRIVILEGES ON *.* TO root@"%" IDENTIFIED BY "root";
mysql>use mysql
mysql>update user set password=password("123456") where user="root";
mysql>flush privileges;
mysql>exit

如果有报错如下：
mysql> GRANT ALL PRIVILEGES ON *.* TO root@"%" IDENTIFIED BY "root";
ERROR 1290 (HY000): The MySQL server is running with the --skip-grant-tables option so it cannot execute this statement

解决办法：先输入flush privileges; 再执行 GRANT ALL PRIVILEGES ON *.* TO root@"%" IDENTIFIED BY "root";其他步骤不要忘记。

（4）[root@localhost ~]#pkill -KILL -t pts/0 可将pts为0的**用户(之前运行mysqld_safe的用户 窗口)强制踢出
（5）正常启动 mysql：service mysqld start
如果没启动mysqld服务就使用mysql,会报错:
[root@localhost ~]# mysql -u root -p
Enter password:
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (111)

7.成功进入mysql

[root@localhost ~]# mysql -u root -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 5
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> show databases;
+----------------------+
| Database |
+----------------------+
| information_schema |
| dbname |
| mysql |
| test |
+----------------------+
4 rows in set (0.00 sec)
mysql>

安全提示：
GRANT ALL PRIVILEGES ON *.* TO root@"%" IDENTIFIED BY "root";
这里最后要做一下IP或网段的限制，否则有安全隐患。