MySQL

表结构同步

下载+安装

从最新版本的linux系统开始，默认的是Mariadb而不是mysql!!！
下载RPM，可以前往MySQL官网进行下载

#5.7
wget http://dev.mysql.com/get/mysql57-community-release-el7-8.noarch.rpm
#5.6
wget http://repo.mysql.com/mysql-community-release-el7-5.noarch.rpm

导入Yum库

yum localinstall mysql57-community-release-el7-8.noarch.rpm
#或者
rpm -ivh mysql-community-release-el7-5.noarch.rpm

安装

yum install mysql-community-server

启动+开机自启

systemctl start mysqld
systemctl status mysqld
systemctl enable mysqld
systemctl daemon-reload

修改root密码

5.6默认无密码，先无密码登录

mysql -u root

5.7会在/var/log/mysqld.log文件中给root生成了一个默认密码

grep 'temporary password' /var/log/mysqld.log

用上面的临时密码登录

mysql -uroot -puAjtkEuj=5.g

再修改密码

ALTER USER 'root'@'localhost' IDENTIFIED BY 'yourpassword';

或者

use mysql;  
update user set password=password('yourpassword') where user='root' and host='localhost';  
flush privileges;

注：5.7 密码字段为 authentication_string，所以应该用下面这条SQL

update user set authentication_string=password("yourpassword") where user='root';

授权root用户远程登录

grant all privileges on *.* to 'root'@'%' identified by 'yourpassword' with grant option;  
flush privileges;

创建用户并授权

CREATE USER 'username'@'%' IDENTIFIED BY 'password';
GRANT ALL ON dbname.* TO 'username'@'%';
FLUSH PRIVILEGES;

MySQL的一些常用的默认文件路径

配置文件：/etc/my.cnf 
日志文件：/var/log//var/log/mysqld.log 
服务启动脚本：/usr/lib/systemd/system/mysqld.service 
socket文件：/var/run/mysqld/mysqld.pid

重置root密码

如果忘记了root密码，则需要通skip-grant-tables方式重置密码

/etc/my.cnf 添加参数 skip-grant-tables
重启mysql
```
systemctl restart mysqld
```
无密码登录
```
mysqld -u root -p
```
设置root密码

FAQ

多版本包冲突

error: Failed dependencies:
    mysql-community-release conflicts with (installed) mysql57-community-release-el7-8.noarch

解决方法

  rpm -e --nodeps mysql57-community-release

GPG key

  GPG key retrieval failed: [Errno 14] curl#37 - "Couldn't open file /etc/pki/rpm-gpg/RPM-GPG-KEY-mysql"

解决方法: https://dev.mysql.com/doc/refman/5.7/en/checking-rpm-signature.html

  rpm --import https://repo.mysql.com/RPM-GPG-KEY-mysql-2022

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