public List getAllUsersWithReservations(int cowlab, List pers, java.util.Date start, java.util.Date end) throws SQLException { String periods = " AND ("; Period p = (Period)pers.get(0); periods = periods + "periodid='"+p.getId()+"'"; for(int i=1;i<pers.size();i++){ Period p1 = (Period)pers.get(i); periods = periods+" or periodid='"+p1.getId()+"') "; } String query = "SELECT * FROM reservations WHERE userid <> '?' and cowlab='?' "+periods+" and date >= '?' and date '?' GROUP BY userid;"; List ls = new ArrayList(); PreparedStatement st = dbcon.prepareStatement(query); st.setInt(1,0); st.setInt(2,cowlab); st.setDate(3,new java.sql.Date(start.getTime())); st.setDate(4,new java.sql.Date(end.getTime())); ResultSet rs = st.executeQuery(); while (rs.next()) { ls.add(String.valueOf(rs.getInt("userid"))); } return ls; }