SELECT MQ.DT_COL,
        SUM(DECODE(IND_COL, 'Y', 1, 0)) NUM_Y,
        SUM(DECODE(IND_COL, 'N', 1, 0)) NUM_N
   FROM ------------------------     
         (
          
          select TRUNC(to_date('2009-01-01', 'yyyy-mm-dd') + level / 3, 'dd') DT_COL,
                  decode(mod(level, 2), 0, 'Y', 'N') IND_COL,
                  round(level*10/3,0) NUM_COL,
                  decode(mod(level, 5), 0, 15, LEVEL) NUM_COL_HAVE_SAME,
                  chr( mod(level-1,26 ) +65 )  TXT_COL_SMALL_CASE,
                  chr( mod(level-1,26 ) +97 )  TXT_COL_CAPTIAL_CASE,
                  decode(mod(level,2),0, chr( mod(level-1,26 ) +65 ),1,chr( mod(level-1,26 ) +97 ))  TXT_COL_ALPHABET
            from dual
          connect by level <= 100
          
          ) MQ
 
 -------------------------
  GROUP BY MQ.DT_COL

?

?

  -----level 101 == level 1 ?
  select to_char(level) || '-' || chr(level), to_char(level + 100) || '-' || chr(level + 100)
    from dual
  connect by level <= 100

?