我得到 *Job for mysql.service 失败，因为控制进程以错误代码退出。
See "systemctl status mysql.service" and "journalctl -xe" for details.*
当我运行该命令时，我得到
? mysql.service - MySQL Community Server
Loaded: loaded (/lib/systemd/system/mysql.service; enabled; vendor preset: enabled)
Active: failed (Result: exit-code) since Mon 2020-04-20 09:32:04 CDT; 19s ago
Process: 7287 ExecStartPre=/usr/share/mysql/mysql-systemd-start pre (code=exited, status=0/SUCCESS)
Process: 7295 ExecStart=/usr/sbin/mysqld (code=exited, status=1/FAILURE)
Main PID: 7295 (code=exited, status=1/FAILURE)
Status: "Server startup in progress"
Error: 13 (Permission denied)
Apr 20 09:32:04 sturtz.ml systemd[1]: mysql.service: Service RestartSec=100ms expired, scheduling restart.
Apr 20 09:32:04 sturtz.ml systemd[1]: …