Preparing statement: select
     clli, traffic_date, count(distinct(traffic_hour))
  from
     gvc_traffic30
 where
    traffic_date in (?)
      and
    clli         in (?,?)
      and
    traffic_hour in (?)
      and
    traffic_type = 'N'
group by
     clli, traffic_date, traffic_hour

running with args  : 01-Jul-2002 switch1 switch2 10