I have a need to copy the contents/data from an additional field set as a pick list to a new field set as a multi-pick list as part of a redesign of some of our fields. Since we are limited on the number of fields we can have and I can't lose the existing data we need to copy it to the new field and then be able to repurpose the field its replacing.

This would require manually updating several thousand tickets. Obviously I'd like to script this so we don't have to touch each record. 

I believe field/form rules would require us to at least edit each ticket for a script to work.  

Is there another method to do this ? I am guessing backend SQL is the only method... but wanted to see if the tool has some functionality to accomplish this.