Hello
When I try to remove mysql, zypper say me that some new packages will be installed
zypper remove mysql-community-server-client
The following 3 NEW packages are going to be installed:
mariadb mariadb-client mariadb-errormessages
The following 2 packages are going to be REMOVED:
mysql-community-server mysql-community-server-client
Why? this behavior can be changed ?
Best Regards, Paul
Some things depend on having a SQL server so if you remove mysql it will want to install mariadb. Actually maria is the normal default these days
Is there a reason you don’t want any SQL database? 
Right. Mariadb is a drop-in replacement for MySQL by the original MySQL author, and is installed by default since a few years (I think since 13.1, might have been 12.3 already though). Both provide a “mysql-server”.
In a default KDE installation, at least Amarok, Akonadi, and digikam need some "mysql-server, i.e. mysql-community-server or mariadb, to be installed. (though digikam uses sqlite by default)
You can of course lock mariadb, then a “zypper remove mysql-community-server” will offer you to uninstall everything that requires mysql/mariadb.