[Koha] Searching for fields with no data

I would like to search and find records without data in a specific field. An example: Go to advanced search in the OPAC and opt for More options. Search with some word in the "Title" field and in the field "Conference name" I would like to find those records that has no data in that field. I can solve this specific question with a SQL report but I wonder if it is possible to do the same with a simple search? ----------------------------- Claes Eriksson Information specialist Department of Communication, Marketing and Library Swedish National Road and Transport Research Institute (VTI) VTI, SE-581 95 Linkoeping, Sweden ----------------------------------