环境：centos7 mysql8.0.18
编译安装参见：https://www.cnblogs.com/fanshudada/p/9781794.html
下面使用rpm安装
一、下载mysql服务软件包
地址：https://dev.mysql.com/downloads/mysql/
rpm package:是某个特定的包，比如server,client,devle等
rpm bundle：是该版本所有包的集合
Compressed TAR Archive，是源码，必须用源码方式安装
Compatibility Libraries：兼容库
Shared Libraries：共享库
Development Libraries：开发库
Test Suite：测试套件
Client Utilities：客户端工具
下载时注意选则好对应的版本
二、安装
相关依赖包：openssl openssl-devel libaio libaio-devel
（1）rpm -ivh mysql-community-libs-8.0.18-1.el7.x86_64
报错信息：
error: Failed dependencies:
mariadb-libs is obsoleted by mysql-community-libs-8.0.18-1.el7.x86_64
原因：mariadb-libs和 mysql-community-libs冲突
解决办法：卸载mariadb-libs
a.查询mariadb-libs的包名
[root@izm5e8nyz28va3a786y465z src]# rpm -qa |grep mariadb
mariadb-libs-5.5.64-1.el7.x86_64
b.卸载该包
[root@izm5e8nyz28va3a786y465z src]# rpm -ev mariadb-libs-5.5.64-1.el7.x86_64 或 rpm -ev --nodeps 包名 （不卸载相关依赖）
error: Failed dependencies:
libmysqlclient.so.18()(64bit) is needed by (installed) postfix-2:2.10.1-7.el7.x86_64
libmysqlclient.so.18(libmysqlclient_18)(64bit) is needed by (installed) postfix-2:2.10.1-7.el7.x86_64
报错原因：postfix是mariadb 的依赖包，要先卸载它
[root@izm5e8nyz28va3a786y465z src]# rpm -qa |grep postfix
postfix-2.10.1-7.el7.x86_64
[root@izm5e8nyz28va3a786y465z src]# rpm -ev postfix-2.10.1-7.el7.x86_64
error: Failed dependencies:
/usr/sbin/sendmail is needed by (installed) redhat-lsb-core-4.1-27.el7.centos.1.x86_64
[root@izm5e8nyz28va3a786y465z src]# rpm -qa |grep redhat-lsb
redhat-lsb-core-4.1-27.el7.centos.1.x86_64
redhat-lsb-submod-security-4.1-27.el7.centos.1.x86_64
[root@izm5e8nyz28va3a786y465z src]# rpm -ev redhat-lsb-core-4.1-27.el7.centos.1.x86_64
Preparing packages...
redhat-lsb-core-4.1-27.el7.centos.1.x86_64
[root@izm5e8nyz28va3a786y465z src]# rpm -ev postfix-2.10.1-7.el7.x86_64
Preparing packages...
postfix-2:2.10.1-7.el7.x86_64
上述步骤成功卸载掉mariadb-libs的依赖
[root@izm5e8nyz28va3a786y465z src]# rpm -ev mariadb-libs-5.5.64-1.el7.x86_64
Preparing packages...
mariadb-libs-1:5.5.64-1.el7.x86_64
继续安装：
[root@izm5e8nyz28va3a786y465z src]# rpm -ivh mysql-community-libs-8.0.18-1.el7.x86_64.rpm
warning: mysql-community-libs-8.0.18-1.el7.x86_64.rpm: Header V3 DSA/SHA1 Signature, key ID 5072e1f5: NOKEY
Preparing... ################################# [100%]
Updating / installing...
1:mysql-community-libs-8.0.18-1.el7################################# [100%]
mysql-community-libs-8.0.18-1.el7包安装成功
（2） rpm -ivh mysql-community-common-8.0.18-1.el7.x86_64.rpm
（3） rpm -ivh mysql-community-client-8.0.18-1.el7.x86_64.rpm
（4） rpm -ivh mysql-community-server-8.0.18-1.el7.x86_64.rpm
error: Failed dependencies:
libaio.so.1()(64bit) is needed by mysql-community-server-8.0.18-1.el7.x86_64
libaio.so.1(LIBAIO_0.1)(64bit) is needed by mysql-community-server-8.0.18-1.el7.x86_64
libaio.so.1(LIBAIO_0.4)(64bit) is needed by mysql-community-server-8.0.18-1.el7.x86_64
解决依赖关系：
[root@izm5e8nyz28va3a786y465z src]# yum list |grep libaio
libaio.i686 0.3.109-13.el7 base
libaio.x86_64 0.3.109-13.el7 base
libaio-devel.i686 0.3.109-13.el7 base
libaio-devel.x86_64 0.3.109-13.el7 base
查询到4个相关的依赖包，只需安装libaio.x86_64 libaio-devel.x86_64
yum -y install libaio.x86_64 libaio-devel.x86_64
[root@izm5e8nyz28va3a786y465z src]# rpm -ivh mysql-community-server-8.0.18-1.el7.x86_64.rpm
warning: mysql-community-server-8.0.18-1.el7.x86_64.rpm: Header V3 DSA/SHA1 Signature, key ID 5072e1f5: NOKEY
Preparing... ################################# [100%]
Updating / installing...
1:mysql-community-server-8.0.18-1.e################################# [100%]
（5）rpm -ivh mysql-community-devel-8.0.18-1.el7.x86_64.rpm
error: Failed dependencies:
pkgconfig(openssl) is needed by mysql-community-devel-8.0.18-1.el7.x86_64
解决依赖关系：
yum -y install openssl openssl-devel
[root@izm5e8nyz28va3a786y465z src]# rpm -ivh mysql-community-devel-8.0.18-1.el7.x86_64.rpm
warning: mysql-community-devel-8.0.18-1.el7.x86_64.rpm: Header V3 DSA/SHA1 Signature, key ID 5072e1f5: NOKEY
Preparing... ################################# [100%]
Updating / installing...
1:mysql-community-devel-8.0.18-1.el################################# [100%]
至此Mysql安装成功
小结：1. 卸载掉冲突组件 mariadb
rpm -ev redhat-lsb-core-4.1-27.el7.centos.1.x86_64 postfix-2.10.1-7.el7.x86_64 mariadb-libs-5.5.64-1.el7.x86_64
2.安装相关依赖：
yum -y install openssl openssl-devel libaio libaio-devel
三、mysql服务设置
1.启动mysql服务：systemctl start mysqld.service
查看MySQL服务是否启动：netstat -tunpl |grep mysqld
2.登录MySQL修改密码
（1）登录mysql
2种方法：跳过密码验证登录 或 查看初始密码登录
a.查看初始密码登录
cat /var/log/mysqld.log
... 2019-11-11T14:28:57.523108Z 5 [Note] [MY-010454] [Server] A temporary password is generated for root@localhost: ,2sg6>HrQdF!
标红加粗部分为初始密码 mysql -uroot -p 键入密码可以登录MySQL
b.跳过密码验证登录
修改my.cnf文件，在[mysqld]区域下加入skip-grant-tables 重启MySQL
[root@izm5e8nyz28va3a786y465z ~]# find / -name my.cnf
/etc/my.cnf
[root@izm5e8nyz28va3a786y465z ~]# vim /etc/my.cnf
[root@izm5e8nyz28va3a786y465z run]# systemctl restart mysqld.service
[root@izm5e8nyz28va3a786y465z run]# mysql #可直接登录MySQL
注意：修改密码后，将my.cnf文件内容还原
（2）修改密码,2sg6>HrQdF!sf
mysql> alter user 'root'@'localhost' identified by 'root123';
ERROR 1819 (HY000): Your password does not satisfy the current policy requirements
原因：密码设置的太过简单，初始密码方针：必须包含数字、大写字母、小写字母、特殊符号、长度8位以上。
mysql> flush privileges;
3.设置字符编码（从MySQL8.0开始，默认字符集就是utf8mb4 了）
# 当前session
set session character_set_server='utf8';
set session collation_server='utf8_bin';
set names 'utf8';
# 全局
set global character_set_server='utf8';
set global collation_server='utf8_bin';
#配置文件（/etc/my.cnf）
[client]
default-character-set = utf8mb4 #客户端字符编码
[mysqld]
character-set-server = utf8mb4 #服务端字符编码
查看默认字符集：
show global variables like '%character_set%';
查看支持的字符集：
show character set;
4.设置远程登录用户和密码
1.设置已有用户远程登录
update user set Host='%' where User='root';
flush privileges;
2.新建远程登录用户
mysql> create user 'xiaobai' identified by 'Abc1234!';
mysql> grant all privileges on *.* to 'xiaobai'@'%' with grant option;
mysql>flush privileges;
连接失败，提示 验证插件'caching_sha2_password'不能loade
原因：新版本的MySQL使用的是caching_sha2_password验证方式，但此时的navicat还没有支持这种验证方式
解决办法：更改加密方式
查看用户加密方式：
mysql> select user,plugin from user where user='root';
+------+-----------------------+
| user | plugin |
+------+-----------------------+
| root | caching_sha2_password |
+------+-----------------------+
更改加密方式：
mysql> alter user 'root'@'%' identified by ',2sg6>HrQdF!sf' password expire never; #设置密码永不过期（此步非必须）
mysql> ALTER USER 'root'@'%' identified with mysql_native_password BY ',2sg6>HrQdF!sf'; #设置为老的加密方式
mysql> select user,plugin from user where user='root'; #加密方式已修改成功
+------+-----------------------+
| user | plugin |
+------+-----------------------+
| root | mysql_native_password |
+------+-----------------------+
刷新权限：flush privileges #可连接成功