>
>Right. I know it's in VBA help but I didn't dig that far. Meanwhile my colleague confirmed, that the query worked great. Now he needs some explanation why it works.
>
>That's what I sent him, may be you can phrase it better:
>
>We need to select patient + date where patient + date are in the result. E.g. we are doing two selects. The inner select filters the data using group by and having and the outer select brings the rest of the data.


Is that whole Select?

select * from Visits;
       INNER JOIN DOCTORS ON VISITS.doctor_name = DOCTORS.doctor_name;
where patient_name + CStr(date) in;
  (SELECT VISITS.patient_name+CStr(VISITS.visit_date)
          FROM VISITS GROUP BY VISITS.patient_name, VISITS.visit_date
          HAVING count(VISITS.visit_date)>1)