Root or Admin User Not Present in mysql.user (only mysql.infoschema, mysql.session, mysql.sys) - mysql

Question

[?] What should I do to normally do sudo mysql -u root -p if it always returns Access denied? [MySQL 8.0] [Ubuntu 20.04]
After clean uninstall mysql and mariadb, then install mysql, at first I got some errors but I can fix it (by configuring my.cnf file and do mysqld --upgrade=force), then finally the mysql service can be started.
However, I got this error whenever tried to access mysql root user
$ sudo mysql -u root -p
Enter password:
ERROR 1045 (28000): Access denied for user 'root'#'localhost' (using password: NO)
Please, I really need help for this :(
And please elaborate me about what I should do to complete the given steps, I'm afraid I don't really understand the basic of Ubuntu system :(
Thank you so much for any effort you guys tried to help me, I really really appreciate it!
What I Tried
To at least access mysql, I add skip-grant-tables on my.cnf.
(However, I cannot do anything such as create user, etc, both inside and outside safe configuration mode.)
$ sudo mysql -u root -p # this only uses blank password
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 7
Server version: 8.0.31-0ubuntu0.20.04.2 (Ubuntu)
Copyright (c) 2000, 2022, Oracle and/or its affiliates.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> SELECT USER();
+--------+
| USER() |
+--------+
| root# |
+--------+
1 row in set (0,01 sec)
mysql> CREATE USER 'root'#'localhost' IDENTIFIED BY 'root';
ERROR 1290 (HY000): The MySQL server is running with the --skip-grant-tables option so it cannot execute this statement
mysql> SELECT user, host FROM mysql.user;
+------------------+-----------+
| user | host |
+------------------+-----------+
| mysql.infoschema | localhost |
| mysql.session | localhost |
| mysql.sys | localhost |
+------------------+-----------+
3 rows in set (0,00 sec)
mysql> SELECT * FROM mysql.user\G
*************************** 1. row ***************************
Host: localhost
User: mysql.infoschema
Select_priv: Y
Insert_priv: N
Update_priv: N
Delete_priv: N
Create_priv: N
Drop_priv: N
Reload_priv: N
Shutdown_priv: N
Process_priv: N
File_priv: N
Grant_priv: N
References_priv: N
Index_priv: N
Alter_priv: N
Show_db_priv: N
Super_priv: N
Create_tmp_table_priv: N
Lock_tables_priv: N
Execute_priv: N
Repl_slave_priv: N
Repl_client_priv: N
Create_view_priv: N
Show_view_priv: N
Create_routine_priv: N
Alter_routine_priv: N
Create_user_priv: N
Event_priv: N
Trigger_priv: N
Create_tablespace_priv: N
...
*************************** 2. row ***************************
Host: localhost
User: mysql.session
Select_priv: N
Insert_priv: N
Update_priv: N
Delete_priv: N
Create_priv: N
Drop_priv: N
Reload_priv: N
Shutdown_priv: Y
Process_priv: N
File_priv: N
Grant_priv: N
References_priv: N
Index_priv: N
Alter_priv: N
Show_db_priv: N
Super_priv: Y
Create_tmp_table_priv: N
Lock_tables_priv: N
Execute_priv: N
Repl_slave_priv: N
Repl_client_priv: N
Create_view_priv: N
Show_view_priv: N
Create_routine_priv: N
Alter_routine_priv: N
Create_user_priv: N
Event_priv: N
Trigger_priv: N
Create_tablespace_priv: N
...
*************************** 3. row ***************************
Host: localhost
User: mysql.sys
Select_priv: N
Insert_priv: N
Update_priv: N
Delete_priv: N
Create_priv: N
Drop_priv: N
Reload_priv: N
Shutdown_priv: N
Process_priv: N
File_priv: N
Grant_priv: N
References_priv: N
Index_priv: N
Alter_priv: N
Show_db_priv: N
Super_priv: N
Create_tmp_table_priv: N
Lock_tables_priv: N
Execute_priv: N
Repl_slave_priv: N
Repl_client_priv: N
Create_view_priv: N
Show_view_priv: N
Create_routine_priv: N
Alter_routine_priv: N
Create_user_priv: N
Event_priv: N
Trigger_priv: N
Create_tablespace_priv: N
...
3 rows in set (0,00 sec)
Also error on doing secure installation
$ mysql_secure_installation
Securing the MySQL server deployment.
Enter password for user root:
Error: Access denied for user 'root'#'localhost' (using password: YES)
my.cnf file
[client]
port = 3306
socket = /var/run/mysqld/mysqld.sock
[mysqld_safe]
socket = /var/run/mysqld/mysqld.sock
nice = 0
[mysqld]
user = mysql
pid-file = /var/run/mysqld/mysqld.pid
socket = /var/run/mysqld/mysqld.sock
port = 3306
basedir = /usr
datadir = /var/lib/mysql
tmpdir = /tmp
lc_messages_dir = /usr/share/mysql
lc_messages = en_US
skip-external-locking
# skip-grant-tables
bind-address = 127.0.0.1
max_connections = 100
connect_timeout = 5
wait_timeout = 600
max_allowed_packet = 16M
thread_cache_size = 128
sort_buffer_size = 4M
bulk_insert_buffer_size = 16M
tmp_table_size = 32M
max_heap_table_size = 32M
myisam_recover_options = BACKUP
key_buffer_size = 128M
table_open_cache = 400
myisam_sort_buffer_size = 512M
concurrent_insert = 2
read_buffer_size = 2M
read_rnd_buffer_size = 1M
# general_log_file = /var/log/mysql/mysql.log
slow_query_log_file = /var/log/mysql/mariadb-slow.log
long_query_time = 10
log_bin = /var/log/mysql/mariadb-bin
log_bin_index = /var/log/mysql/mariadb-bin.index
default_storage_engine = InnoDB
innodb_buffer_pool_size = 256M
innodb_log_buffer_size = 8M
innodb_file_per_table = 1
innodb_open_files = 400
innodb_io_capacity = 400
innodb_flush_method = O_DIRECT
[galera]
[mysqldump]
quick
quote-names
max_allowed_packet = 16M
[mysql]
[isamchk]
key_buffer = 16M
# Error handling after installation by commenting this out
# system status error handling (these variables unknown)
# query_cache_limit = 128K
# query_cache_size = 64M
# expire_logs_days = 10
# max_binlog_size = 100M
# $ mysqld --upgrade=force error handling (these variables unknown)
# log_warnings = 2
# log_slow_verbosity = query_plan
MySQL status
$ sudo systemctl status mysql
● mysql.service - MySQL Community Server
Loaded: loaded (/lib/systemd/system/mysql.service; enabled; vendor preset: enabled)
Active: active (running) since Thu 2022-12-01 14:40:12 WIB; 12min ago
Main PID: 247973 (mysqld)
Status: "Server is operational"
Tasks: 38 (limit: 6878)
Memory: 312.6M
CGroup: /system.slice/mysql.service
└─247973 /usr/sbin/mysqld
Des 01 14:40:04 EMP10 systemd[1]: Starting MySQL Community Server...
Des 01 14:40:05 EMP10 mysqld[247973]: 2022-12-01T07:40:05.235618Z 0 [System] [MY-010116] [Server] /usr/sbin/mysqld (mysqld 8.0.31-0ubuntu0.20.04.2) starting as process 247973
Des 01 14:40:05 EMP10 mysqld[247973]: 2022-12-01T07:40:05.272065Z 1 [System] [MY-013576] [InnoDB] InnoDB initialization has started.
Des 01 14:40:09 EMP10 mysqld[247973]: 2022-12-01T07:40:09.042423Z 1 [System] [MY-013577] [InnoDB] InnoDB initialization has ended.
Des 01 14:40:12 EMP10 mysqld[247973]: 2022-12-01T07:40:12.258475Z 0 [Warning] [MY-010068] [Server] CA certificate ca.pem is self signed.
Des 01 14:40:12 EMP10 mysqld[247973]: 2022-12-01T07:40:12.258535Z 0 [System] [MY-013602] [Server] Channel mysql_main configured to support TLS. Encrypted connections are now supported for this channel.
Des 01 14:40:12 EMP10 mysqld[247973]: 2022-12-01T07:40:12.474475Z 0 [System] [MY-011323] [Server] X Plugin ready for connections. Bind-address: '::' port: 33060, socket: /var/run/mysqld/mysqlx.sock
Des 01 14:40:12 EMP10 mysqld[247973]: 2022-12-01T07:40:12.474611Z 0 [System] [MY-010931] [Server] /usr/sbin/mysqld: ready for connections. Version: '8.0.31-0ubuntu0.20.04.2' socket: '/var/run/mysqld/mysqld.sock' port: 3306 (Ubuntu).
Des 01 14:40:12 EMP10 systemd[1]: Started MySQL Community Server.
Actually, if the suggestion is only to uninstall and install mysql, the later installing always gives me errors to handle :(
I usually did these to clean uninstall and install mysql
$ sudo systemctl stop mysql
$ dpkg -l | grep mysql
ii mysql-client-8.0 8.0.31-0ubuntu0.20.04.2 amd64 MySQL database client binaries
ii mysql-client-core-8.0 8.0.31-0ubuntu0.20.04.2 amd64 MySQL database core client binaries
ii mysql-common 1:10.3.37+maria~ubu1804 all MariaDB database common files (e.g. /etc/mysql/my.cnf)
ii mysql-server 8.0.31-0ubuntu0.20.04.2 all MySQL database server (metapackage depending on the latest version)
ii mysql-server-8.0 8.0.31-0ubuntu0.20.04.2 amd64 MySQL database server binaries and system database setup
ii mysql-server-core-8.0 8.0.31-0ubuntu0.20.04.2 amd64 MySQL database server binaries
$ sudo apt remove --purge mysql-client-* mysql-common mysql-server*
$ sudo rm -rf /etc/mysql /var/lib/mysql /var/log/mysql
$ sudo apt autoremove
$ sudo apt autoclean
$ sudo apt install mysql-server # or $ sudo apt install mysql-server-8.0 mysql-server-core-8.0
After installation, there must be something errors to handle.
Reinstalling also didn't fix
$ sudo apt install --reinstall mysql-server # or $ sudo apt install mysql-server-8.0 mysql-server-core-8.0