我已经将php从5.6版升级到7.2版，现在mysql不工作了。我进去的时候 sudo service mysqsl start ，将显示以下文本：

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

的输出 journalctl -xe 的输出 systemctl status mysql.service :

mysql.service - LSB: Start and stop the mysql database server daemon
   Loaded: loaded (/etc/init.d/mysql)
   Active: failed (Result: exit-code) since \u0633\u0647\u200c\u0634\u0646\u0628\u0647 2018-07-17 04:22:01 +0430; 27s ago
     Docs: man:systemd-sysv-generator(8)
  Process: 26938 ExecStop=/etc/init.d/mysql stop (code=exited, status=0/SUCCESS)
  Process: 6860 ExecStart=/etc/init.d/mysql start (code=exited, status=1/FAILURE)
 Main PID: 9974 (code=exited, status=0/SUCCESS)

\u0698\u0648\u0626\u06cc\u0647 17 04:22:01 hutadmin-virtual-machine mysql[6860]: [97B blob data]
\u0698\u0648\u0626\u06cc\u0647 17 04:22:01 hutadmin-virtual-machine mysql[6860]: Fatal error in defaults handling. Program aborted
\u0698\u0648\u0626\u06cc\u0647 17 04:22:01 hutadmin-virtual-machine /etc/init.d/mysql[7565]: 0 processes alive and '/usr/bin/mysqladmin --defaults-file=/etc/mysql/debian.cnf ping' resulted in
\u0698\u0648\u0626\u06cc\u0647 17 04:22:01 hutadmin-virtual-machine /etc/init.d/mysql[7565]: [61B blob data]
\u0698\u0648\u0626\u06cc\u0647 17 04:22:01 hutadmin-virtual-machine /etc/init.d/mysql[7565]: error: 'Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)'
\u0698\u0648\u0626\u06cc\u0647 17 04:22:01 hutadmin-virtual-machine mysql[6860]: ...fail!
\u0698\u0648\u0626\u06cc\u0647 17 04:22:01 hutadmin-virtual-machine systemd[1]: mysql.service: Control process exited, code=exited status=1
\u0698\u0648\u0626\u06cc\u0647 17 04:22:01 hutadmin-virtual-machine systemd[1]: Failed to start LSB: Start and stop the mysql database server daemon.
\u0698\u0648\u0626\u06cc\u0647 17 04:22:01 hutadmin-virtual-machine systemd[1]: mysql.service: Unit entered failed state.
\u0698\u0648\u0626\u06cc\u0647 17 04:22:01 hutadmin-virtual-machine systemd[1]: mysql.service: Failed with result 'exit-code'.

我怎样才能解决这个问题？我需要启动mysql。