I tried to uninstall (sudo pacman -Rns mariadb , sudo pacman -Rns mysql ) mySQL so i can re-install because i had some problems.
But i doesn’t remove the files so every time i re-install it i run to the same problems
Should i remove all files and directories with mysql on the name or is this dangerous?
Is there another way to complete remove mySQL and MariaDB from my pc?
Thank you!
you need to remove also all remnants from the home folder
What problems?
sudo find / -iname mysql
AFAIK this will give you remnants of your mysql in your / folder
and any other directory lying inside your / folder
do note any name that you place after -iname is case insensitive meaning if you search “foo”… it will show you result all related to foo like foobar foot etc.
you can learn about find through
man find
whilst deleting do note not to delete files and documents that are not affiliated to other program… you might run into other issue otherwise… and while deleting use sudo and rm command carefully
Have a nice day 
Default datadir would be /var/lib/mysql/ IIRC:
$ sudo ls -lh /var/lib/mysql/
possibly followed by
$ rm -fr /var/lib/mysql/
to remove it.