MySQL基本操作记录

• 开启远程登录（或局域网访问）

use mysql;
GRANT ALL PRIVILEGES ON *.* TO 'root'@'%' IDENTIFIED BY 'root' WITH GRANT OPTION;
flush privileges;
select host,user from user;

• Access denied for user ''@'localhost' to database 'mysql'

1. 关闭mysql
   service mysqld stop
2. 屏蔽权限
   mysqld_safe --skip-grant-table
   屏幕出现： Starting demo from .....
3. 新开起一个终端输入
   mysql -u root mysql
   mysql> delete from user where USER='';
   mysql> FLUSH PRIVILEGES;//记得要这句话，否则如果关闭先前的终端，又会出现原来的错误
   mysql> \q

• centos7安装mysql

1. 下载、安装仓库

在命令行中输入

wget -i -c http://dev.mysql.com/get/mysql57-community-release-el7-10.noarch.rpm

2. 安装本地包

yum -y install mysql57-community-release-el7-10.noarch.rpm

3. 安装mysql

yum -y install mysql-community-server

4. 启动mysql，然后查看启动状态

systemctl start  mysqld.service

systemctl status mysqld.service

5. 查看root的随机密码

grep "password" /var/log/mysqld.log

6. 使用随机密码登录mysql

mysql -uroot -p
# 输入上步找到的密码

7. 修改默认密码

# 先修改密码规则，可以使用简单密码
mysql> set global validate_password_policy=0;
mysql> set global validate_password_length=1;

mysql> ALTER USER 'root'@'localhost' IDENTIFIED BY 'new password';

8. 删除本地仓库，已免经常更新

yum -y remove mysql57-community-release-el7-10.noarch

• mysql编码utf8

1. 查看当前编码

show variables like 'character%'

mysql> show variables like 'character%';
+--------------------------+----------------------------+
| Variable_name            | Value                      |
+--------------------------+----------------------------+
| character_set_client     | utf8                       |
| character_set_connection | utf8                       |
| character_set_database   | latin1                     |
| character_set_filesystem | binary                     |
| character_set_results    | utf8                       |
| character_set_server     | latin1                     |
| character_set_system     | utf8                       |
| character_sets_dir       | /usr/share/mysql/charsets/ |
+--------------------------+----------------------------+
8 rows in set (0.00 sec)

2. 修改配置中编码

# 退出mysql
exit
# 然后编辑配置文件
[root@VM_0_14_centos ~]# vim /etc/my.cnf
# 在[mysqld] 下面添加下行数据
character_set_server=utf8
# 保存退出
:wq

3. 重启mysql

systemctl restart mysqld

• mysql导入导出

1. mysql数据库导出
   输入以下命令之后再输入密码即可导出到指定位置

[root@VM_0_14_centos ~]# mysqldump -uroot -p nhh_vendor_management_test > /root/vm.sql

2. mysql数据库导入
   登录数据并新建数据库

create datatable dbname;

导入数据库

[root@VM_0_14_centos ~]# mysql -uroot -p vm < /root/vm.sql