Linux上安装mysql8.0，安装过程及遇到的错误总结

安装过程，不再赘述，参考https://blog.youkuaiyun.com/qq_31382921/article/details/53696031
以及https://blog.youkuaiyun.com/u012946310/article/details/81880050问题都能解决；
特别注意：mysql启动服务是service mysqld start 是mysqld不是mysql。

一、mysql安装过程

补充安装过程：（之前安装好了之后，发现第二次安装又遇到不成功的问题，随将过程大概记录一下）

1. 检查系统里面之前有没有安装过mysql数据库，为了防止卸载不干净，导致安装失败，先进行检查

基本rpm使用语句：

1. 查看有没有旧版本 的mysql rpm -qa | grep -i mysql
2. 卸载旧版本的mysql rpm -ev mysql-libs-5.1.71-1.el6.x86_64
3. 2019/06/17刚发现的批量卸载命令：rpm -qa | grep -i mysql | xargs rpm -ev --nodeps
   如果无法卸载，请加上 --nodeps,忽略依赖，进行强制卸载
4. 查找mysql 文件的出现过的安装位置 find / -name mysql，其中配置文件/etc/my.cnf需要手动删除

[root@localhost mysql]# rpm -qa | grep -i mysql                           
mysql-community-libs-compat-8.0.15-1.el6.x86_64
mysql-community-common-8.0.15-1.el6.x86_64
mysql-community-libs-8.0.15-1.el6.x86_64
mysql-community-client-8.0.15-1.el6.x86_64

[root@localhost mysql]# rpm -ev mysql-community-libs-compat-8.0.15-1.el6.x86_64 --nodeps
warning:    erase unlink of /usr/lib64/mysql/libmysqlclient_r.so.16.0.0 failed: No such file or directory
warning:    erase unlink of /usr/lib64/mysql/libmysqlclient_r.so.16 failed: No such file or directory
warning:    erase unlink of /usr/lib64/mysql/libmysqlclient.so.16.0.0 failed: No such file or directory
warning:    erase unlink of /usr/lib64/mysql/libmysqlclient.so.16 failed: No such file or directory

[root@localhost mysql]# rpm -qa | grep -i mysql
mysql-community-common-8.0.15-1.el6.x86_64
mysql-community-libs-8.0.15-1.el6.x86_64
mysql-community-client-8.0.15-1.el6.x86_64

[root@localhost mysql]# rpm -ev mysql-community-common-8.0.15-1.el6.x86_64 --nodeps

[root@localhost mysql]# rpm -ev mysql-community-libs-8.0.15-1.el6.x86_64 --nodeps
warning:    erase unlink of /usr/lib64/mysql/libmysqlclient.so.21.0.15 failed: No such