TOPIC: Additional information into hidden field

A customer wants some additional information in the backoffice. The registrations are already open, the've got a lot of subscribers but now they find out they are missing some information.

What they want is the event descibtions (event_describe from table dtregister_group_event) into a hidden field so they can see this information when the consult the registrationrecords in the backoffice.

If i'm right i need to update the table dtregister_user_field_values using the tables dtregister_group_event (for the even_describe) and table dtregister_user to link those tables (userid and eventid).

Who can help? How should the SQL statement look like? :

Thank you!

Jos