Package name question

[Bitfox]

Hello

After I installed mysql 8.0 via apt install mysql-server, I tried to 
restart mysql server.

I issued the following commands,

systemctl restart mysql-server
systemctl restart mysqld

They got failed, no package was found.

Then I run systemctl restart mysql it successed finally.

My question is how I can know the installed package name rather than by 
guessing?

Thanks