Query with row_number=1

Question

Can any one please tell me whats wrong with the following query:
SELECT   number_of_days
       - (TRUNC ((number_of_days - first_weekend) / 7) + 1)
       - (TRUNC ((number_of_days - first_weekend - 1) / 7) + 1) weekdays,
       ROW_NUMBER () OVER (ORDER BY month_end) r
  FROM (SELECT EXTRACT (DAY FROM NEXT_DAY (TRUNC (input_date, 'MM'),
                                           'SATURDAY'
                       ) first_weekend,
               LAST_DAY (input_date) month_end,
               EXTRACT (DAY FROM LAST_DAY (input_date)) number_of_days
          FROM (SELECT TO_DATE (date_read, 'YYYY-MM-DD') input_date
                  FROM its_sensor_15min))
WHERE r = 1Thanks
PS: I'm getting "r invalid identifier" error
Edited by: thinkingeye on Jul 30, 2010 1:39 PM

Answer 1

Thanks all
But when i used my initial query its giving me an error again
SELECT   TO_CHAR (TRUNC (date_read, 'mm'),
                  'MON-YYYY',
                  'nls_date_language=english'
                 ) month_year,
        (select weekdays,r
from(
SELECT   number_of_days
       - (TRUNC ((number_of_days - first_weekend) / 7) + 1)
       - (TRUNC ((number_of_days - first_weekend - 1) / 7) + 1) weekdays,
       ROW_NUMBER () OVER (ORDER BY month_end) r
  FROM (SELECT EXTRACT (DAY FROM NEXT_DAY (TRUNC (input_date, 'MM'),
                                           'SATURDAY'
                       ) first_weekend,
               LAST_DAY (input_date) month_end,
               EXTRACT (DAY FROM LAST_DAY (input_date)) number_of_days
          FROM (SELECT TO_DATE (date_read, 'YYYY-MM-DD') input_date
                  FROM its_sensor_15min)))where r=1 ,
         COUNT (CASE
                   WHEN speed_avg <= 45
                   AND speed_avg != 0
                   AND vol_sum != 0
                   AND lane_type = 'm'
                   AND (hour_read || qtrhr_read) IN
                          ('61', '62', '63', '64', '71', '72', '73', '74',
                           '81', '82', '83', '84', '153', '154', '161', '162',
                           '163', '164', '171', '172', '173', '174', '181',
                           '182')
                      THEN 1
                END
               ) count_rows_less_than_45,
         (  COUNT (CASE
                      WHEN speed_avg <= 45
                      AND speed_avg != 0
                      AND vol_sum != 0
                      AND lane_type = 'm'
                      AND (hour_read || qtrhr_read) IN
                             ('61', '62', '63', '64', '71', '72', '73', '74',
                              '81', '82', '83', '84', '153', '154', '161',
                              '162', '163', '164', '171', '172', '173', '174',
                              '181', '182')
                         THEN 1
                   END
          / COUNT (DISTINCT asset_id || direction)
          / 24
         ) count_ratio,
         COUNT (DISTINCT asset_id || direction)
    FROM its_sensor_15min
   WHERE TO_CHAR (date_read, 'fmday') NOT IN ('saturday', 'sunday')
GROUP BY TRUNC (date_read, 'mm')