Counting duplicate in a matrix

Hi johnt75 ,

Thanks for the answer but that would only result in a 'true' value on the start date of every project. 

Colum values Personeels planning = 
VAR currentEmployee =
    SELECTEDVALUE ( 'Input - personeel'[Naam] )
VAR empTable =
    GENERATE (
        SELECTCOLUMNS (
            FILTER ( 'Input - planning', 'Input - planning'[Medewerker] = currentEmployee ),
            "@start date", 'Input - planning'[Startdatum],
            "@end date", 'Input - planning'[Einddatum]
        ),
        DATESBETWEEN ( 'Date table'[Date], [@start date], [@end date] )
    )
VAR summaryTable =
    ADDCOLUMNS (
        SUMMARIZE ( empTable, [Date] ),
        "@num rows", CALCULATE ( COUNTROWS ( empTable ) )
    )
VAR start_datum =
    CALCULATE ( MIN ( 'Input - planning'[Startdatum] ), ALL ( 'Date table' ) )
VAR eind_datum =
    CALCULATE ( MAX ( 'Input - planning'[Einddatum] ), ALL ( 'Date table' ) )
VAR _periode =
    MIN ( 'Date table'[Date] ) >= start_datum
        && MAX ( 'Date table'[Date] ) <= eind_datum
RETURN
    //IF(_periode,1,BLANK()) 
    IF (
        ( ISEMPTY ( FILTER ( summaryTable, [@num rows] > 1 ) ) ),
        ( IF ( _periode, 1, BLANK () ) ),
        2
    )