輸入service mysqld start報錯
報這個錯多半是沒有安裝成功在yum install mysql-community-server的時候報錯
The GPG keys listed for the "MySQL 5.7 Community Server" repository are already installed but they are not correct for this package.
Check that the correct key URLs are configured for this repository.
解決方案：
先執行如下命令
rpm --import https://repo.mysql.com/RPM-GPG-KEY-mysql-2022
再執行安裝命令
yum install mysql-community-server
最後再次service mysqld start
