String sql = "SELECT KURSNAMN FROM KURS join larare on KURSLARARE = LARAR_ID where fornamn || '' || efternamn =" +"'" + comboBoxValjLarare.getSelectedItem() + "'" + " and KURSSTART || KURSSLUT BETWEEN" + "'" + startDatum + "'" + " AND " + "'" slutDatum + "'" + "";