I can't start mysql database, what should I do?

Question

MySQL

# sudo service mysql start
Job for mysql.service failed because the control process exited with error code.
See "systemctl status mysql.service" and "journalctl -xe" for details.

# systemctl status mysql.service
● mysql.service - MySQL Community Server
   Loaded: loaded (/lib/systemd/system/mysql.service; enabled; vendor preset: enabled)
   Active: failed (Result: exit-code) since Fri 2019-07-19 09:57:19 UTC; 29s ago
  Process: 9448 ExecStartPre=/usr/share/mysql/mysql-systemd-start pre (code=exited, status=1/FAILURE)

Jul 19 09:57:19 server-web systemd[1]: Failed to start MySQL Community Server.
Jul 19 09:57:19 server-web systemd[1]: mysql.service: Service hold-off time over, scheduling restart.
Jul 19 09:57:19 server-web systemd[1]: mysql.service: Scheduled restart job, restart counter is at 5.
Jul 19 09:57:19 server-web systemd[1]: Stopped MySQL Community Server.
Jul 19 09:57:19 server-web systemd[1]: mysql.service: Start request repeated too quickly.
Jul 19 09:57:19 server-web systemd[1]: mysql.service: Failed with result 'exit-code'.
Jul 19 09:57:19 server-web systemd[1]: Failed to start MySQL Community Server.

What to do where to dig?