To migrate the SQL custom field plugin from the Server/Datacenter version, the user must manually copy the Datsource and Custaum Field elements.
It is necessary for them to enter each element individually according to their needs.
On the cloud version of the plugin, there are no differences between the elements that exist on the Server/Datacenter version.
You would have no trouble recreating your datasources.
After that, apply the same actions for Custom fields.
You can consult our page which is specifically dedicated to this subject : Comparison of the DC version versus Cloud version of the Kepler - SQL Query Fields plugin.
If you have any questions or need assistance, feel free to contact us in Support.