For openSUSE Leap 15.6 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:marec2000:server:database/openSUSE_Leap_15.6/home:marec2000:server:database.repo
zypper refresh
zypper install mysql-workbench
For openSUSE Leap 15.5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:marec2000:server:database/openSUSE_Leap_15.5/home:marec2000:server:database.repo
zypper refresh
zypper install mysql-workbench
For openSUSE Leap 15.4 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:marec2000:server:database/openSUSE_Leap_15.4/home:marec2000:server:database.repo
zypper refresh
zypper install mysql-workbench
For openSUSE Leap 15.3 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:marec2000:server:database/openSUSE_Leap_15.3/home:marec2000:server:database.repo
zypper refresh
zypper install mysql-workbench