Cannot connect to mysql Local database after upgrade from 18.04 to 20.04 LTS

I cannot connect to MYSQL db and it is a root process:

I have tried the solution:

1. https://dba.stackexchange.com/questions/11027/cant-connect-to-local-mysql-server-through-socket-var-lib-mysql-mysql-sock

but failed

Status of mysql server:

mysql.service - MySQL Community Server
 Loaded: loaded (/lib/systemd/system/mysql.service; enabled; vendor preset: enabled)
 Active: failed (Result: exit-code) since Tue 2020-05-26 15:01:53 IST; 23min ago
Process: 1470 ExecStartPre=/usr/share/mysql/mysql-systemd-start pre (code=exited, status=0/SUCCESS)
Process: 1479 ExecStart=/usr/sbin/mysqld --daemonize --pid-file=/run/mysqld/mysqld.pid (code=exited, status=1/FAILURE)

May 26 15:01:53 user systemd[1]: 
mysql.service: Scheduled restart job, restart counter is at 6.
May 26 15:01:53 user systemd[1]: Stopped MySQL Community Server.
May 26 15:01:53 user systemd[1]: mysql.service: Start request repeated too quickly.
May 26 15:01:53 user systemd[1]: mysql.service: Failed with result 'exit-code'.
May 26 15:01:53 user systemd[1]: Failed to start MySQL Community Server.