Sage Construction & Real Estate

I'm trying to build a report that will allow me to select job costs for a list of jobs that have no work order assigned. How do I set the criteria to select null values?

Does anyone have any comprehensive form of databse schema or detailed data dictionary for Sage 300 CRE when trying to access using ODBC? I have been trying to find one for some time that details the table locations of data fields and have found Sage documentation…