This sounds like a classical classification, right?
If the classification is static (not depending on selections), you want to do this in the script.
You can either do this using conditionals (maybe using some match() functions, too):
if( EducationNr >= 100 and EducationNR <=106, 'University',
if( EducationNr >=546 and EducationNr <= 557, 'Lower Education')) as EduClass,
or e.g. using a mapping table, which is described here: