Re: Q: something like rownum

I believe something like this will do it.

select r_num, the_date, to_char(dates.the_date,'DY') DAY
  from (select rownum r_num, the_date
          from (select the_date from my_table
                  where to_char(dates.the_date,'DY') IN
                     ('MON','TUE','WED','THU','FRI')
                  order by the_date)
        union
        select null r_num, the_date from my_table
          where to_char(dates.the_date,'DY') IN ('SAT','SUN'))
   order by the_date;