在启动MySQL的时候，连接不上：

ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)
root@lueluelue:/opt/app/lueluelue-pc# sudo mysql -u root
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)
root@lueluelue:/opt/app/lueluelue-pc# sudo mysql -u root -p
Enter password:
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)

查看是否启动：

sudo service mysql status

没有启动就启动：

sudo service mysql start

但是启动不成功

sudo service mysql status
Unit mysql.service could not be found.
root@lueluelue:/opt/app/lueluelue-pc# sudo service mysql start
Failed to start mysql.service: Unit mysql.service not found.
root@lueluelue:/opt/app/lueluelue-pc# mysql --version
mysql Ver 8.0.34-0ubuntu0.22.04.1 for Linux on x86_64 ((Ubuntu))
root@lueluelue:/opt/app/lueluelue-pc# which mysql
/usr/bin/mysql

查看是否正确安装：

dpkg -l | grep mysql

ii  libmysqlclient-dev                    8.0.34-0ubuntu0.22.04.1                 amd64        MySQL database development files
ii  libmysqlclient21:amd64                8.0.34-0ubuntu0.22.04.1                 amd64        MySQL database client library
ii  mysql-client-core-8.0                 8.0.34-0ubuntu0.22.04.1                 amd64        MySQL database core client binaries
ii  mysql-common                          5.8+1.0.8                               all          MySQL database common files, e.g. /etc/mysql/my.cnf

进行安装：

sudo apt-get update
sudo apt-get install mysql-server

这时候安装后就自动启动了MySQL：

update-alternatives: using /etc/mysql/mysql.cnf to provide /etc/mysql/my.cnf (my.cnf) in auto mode
Renaming removed key_buffer and myisam-recover options (if present)
mysqld will log errors to /var/log/mysql/error.log
mysqld is running as pid 85477
Created symlink /etc/systemd/system/multi-user.target.wants/mysql.service → /lib/systemd/system/mysql.service.
Setting up libcgi-pm-perl (4.54-1) ...