oracle sql non è un gruppo per espressione durante il conteggio

Per una migliore comprensione, fare riferimento a questo link

 SELECT 
    count(local_doc.providerno) NumberofReferals, 
    LOCAL_DOC.FULLNAME FULLNAME, 
    LOCAL_DOC.TELNUMBER TELNUMBER, 
    LOCAL_DOC.STREET STREET, 
    LOCAL_DOC.SUBURB SUBURB, 
    LOCAL_DOC.STATE STATE, 
    LOCAL_DOC.POSTCODE POSTCODE,
    LOCAL_DOC.PROVIDERNO
FROM 
    LOCAL_DOC, 
    PATIENT 
WHERE 
    PATIENT.PROVIDERNO = LOCAL_DOC.PROVIDERNO AND PATIENT.REFERALDATE <= sysdate AND PATIENT.REFERALDATE >= ADD_MONTHS(sysdate, -6)
GROUP BY
    LOCAL_DOC.FULLNAME , 
    LOCAL_DOC.TELNUMBER , 
    LOCAL_DOC.STREET , 
    LOCAL_DOC.SUBURB , 
    LOCAL_DOC.STATE , 
    LOCAL_DOC.POSTCODE ,
    LOCAL_DOC.PROVIDERNO