linux下关于mysql安装的一些问题

安装mysql时候找不到密码尝试无果后开始卸载重装

 create database testdb;
 create user 'testuser'@'localhost' identified by 'password';
 grant all on testdb.* to 'testuser' identified by 'password';

sudo yum update：更新yum软件
yum update -y 不用按确定一直跟新的
rpm -e 软件包：卸载软件包

rpm -e --nodeps：强制卸载

查看mysql的安装情况

rpm -qa | grep -i mysq

卸载：

1.普通卸载（可能有依赖关系）

rpm -e mysql-community-libs-5.7.18-1.el6.x86_64

2.强制卸载

rpm -e --nodeps mysql-community-libs-5.7.18-1.el6.x86_64

删除mysql服务

[root@localhost local]# chkconfig --list | grep -i mysql
[root@localhost local]# chkconfig --del mysql

在Linux系统下，通过命令“rm -rf”可以将任何数据直接从硬盘删除，并且没有任何提示

删除分散mysql文件夹

[root@localhost local]# whereis mysql 或者 find / -name mysql

mysql: /usr/lib/mysql /usr/share/mysql

清空相关mysql的所有目录以及文件
rm -rf /usr/lib/mysql
rm -rf /usr/share/mysql

rm -rf /usr/my.cnf

下面成功安装mysql服务详细步骤

1.Update your system:

sudo yum update

2.Install and Start MySQL

(1)Install MySQL and tell it which runlevels to start on:

sudo yum install mysql-server
sudo /sbin/chkconfig --levels 235 mysqld on

(2)Then to start the MySQL server:

sudo service mysqld start

3.set password

sudo mysql_secure_installation

回车，回车跳过初始密码

设置新的密码

4.登录mysql

mysql -u root -p

Create a New MySQL User and Database

1. In the example below, testdb is the name of the database, testuser is the user, and passwordis the user’s password.

   create database testdb;
    create user 'testuser'@'localhost' identified by 'password';
    grant all on testdb.* to 'testuser' identified by 'password';

   You can shorten this process by creating the user while assigning database permissions:

2.  create database testdb;
    grant all on testdb.* to 'testuser' identified by 'password';

   
   

3. Then exit MySQL.

4. Create a Sample Table

   mysql -u testuser -p

   
   

use testdb;create table customers (customer_id INT NOT NULL AUTO_INCREMENT PRIMARY KEY, first_name TEXT, last_name TEXT);

重置密码：

If you forget your root MySQL password, it can be flushed and then reset.

1. Stop the current MySQL server instance, then restart it with an option to not ask for a password.

sudo /etc/init.d/mysqld stop
 sudo mysqld_safe --skip-grant-tables &

Reconnect to the MySQL server with the MySQL root account.

mysql -u root

Use the following commands to reset root’s password. Replace password with a strong password.

 use mysql;
 update user SET PASSWORD=PASSWORD("password") WHERE USER='root';
 flush privileges;
 exit

Then restart MySQL.

sudo service mysqld restart

关于数据库乱码问题：

查看数据库字符集

 SHOW VARIABLES LIKE 'character%';

上面是正确的编码

刚开始可能是latint1，全部修改成你需要的编码

#vim /etc/mysql/my.cnf (5.5以前系统)如下修改：

在【client】下面加入 default-character-set=utf8

在【mysqld】下面加入default-character-set=utf8

Notice：注意 如果修改后不能启动报错试试把default-character-set=utf8改为character_set_server=utf8，仅仅加入到mysqld下面的.client就不需要加了

#vim /etc/mysql/my.cnf 。(5.5以后系统)如下修改：

[client]
default-character-set=utf8

[mysqld]
default-storage-engine=INNODB
character-set-server=utf8
collation-server=utf8_general_ci

卸载：参考：http://blog.youkuaiyun.com/rosten/article/details/25096159

安装：参考：https://www.linode.com/docs/databases/mysql/how-to-install-mysql-on-centos-6