Create custom column with with effective dated field

Hi,

I am not sure how your datamodel looks like, but please try the below for creating a new column whether it suits your requirement.

ProfType calculated column =
VAR _max =
    MAXX (
        FILTER (
            ProfessionalType,
            ProfessionalType[EffDate] <= EARLIER ( ProfessionalType[EffDate] )
                && ProfessionalType[ProfessionalType]
                    = EARLIER ( ProfessionalType[ProfessionalType] )
        ),
        ProfessionalType[EffDate]
    )
RETURN
    MAXX (
        FILTER (
            ProfessionalType,
            ProfessionalType[EffDate] = _max
                && ProfessionalType[ProfessionalType]
                    = EARLIER ( ProfessionalType[ProfessionalType] )
        ),
        ProfessionalType[ProfessionalType]
    )