when you want to install the Pentaho client tools to your machine and you have trouble connecting to a MySQL database, there are a few things to keep in mind:
1. the Pentaho-Tools do not ship with a Java MySQL connector. You have to download it from the MySQL website.
2. the latest connector from the MySQL website does not work (versions 8.x)
3. mysql-connector-java-5.1.47 works well for me. Install it by copying it into the respective “lib” / “lib/jdbc” folders
Then your client tools should be working fine.