Get week number for day from a list of days within a year..

Question

I am beginning in ORACLE / SQL and wondering how I can use this query to work with a column of Dates that span over a number of years?
Ideally, I would like to use this script to add a number for the week of the year based on this.
Then when a new year begins to start over..
I am referencing an old thread..
TO_CHAR with dates to get week number issue
Here is what I have so far:
I keep getting an error stating "Bind Variable "p_date_beg" is NOT DECLARED"..
Thanks in advance for any help you can provide.
DECLARE
p_date_beg DATE;
BEGIN
SELECT RETRIEVAL_DATE
INTO P_DATE_BEG
FROM OBS_SELECT_LST12_SPG;
WITH TAB AS
(SELECT TO_DATE(TO_CHAR(:p_date_beg,'YYYYMM')||'01','YYYYMMDD') + LEVEL -1 DATE_COL
FROM DUAL
CONNECT BY LEVEL <=TO_NUMBER(TO_CHAR(LAST_DAY(:p_date_beg),'DD')))
SELECT DATE_COL, TO_CHAR(DATE_COL, 'FMDAY') DAY,
(CASE
WHEN TO_CHAR(TRUNC(DATE_COL, 'mm'),'FMDAY') = 'SUNDAY'
THEN TO_NUMBER(TO_CHAR(DATE_COL,'W'))
ELSE CEIL((TO_CHAR(SYSDATE, 'dd') + 1 - TO_CHAR(NEXT_DAY(TRUNC(SYSDATE, 'mm'), 'SUNDAY'), 'dd'))/7)
END) WEEK_NOB
END;

Answer 1

hi, referring to this link about ISO week, http://www.epochconverter.com/date-and-time/weeknumbers-by-year.php, here is the code:
/* Formatted on 2012/06/13 06:32 (Formatter Plus v4.8.8) */
WITH t AS
     (SELECT     MIN (TO_DATE ('20120101', 'rrrrmmdd') + LEVEL - 1)
                                                                   start_date,
                 1 week_th
            FROM DUAL
           WHERE TO_CHAR (  TRUNC (TO_DATE ('20120101', 'rrrrmmdd'), 'mm')
                          + LEVEL
                          - 1,
                          'FMDAY'
                         ) = 'MONDAY'
             AND (   TO_DATE ('20120101', 'rrrrmmdd') + LEVEL - 1 <
                        TRUNC (NEXT_DAY (TO_DATE ('20120101', 'rrrrmmdd'),
                                         'THU'
                  OR (TO_DATE ('20120101', 'rrrrmmdd') + LEVEL - 1
                         BETWEEN TRUNC (NEXT_DAY (TO_DATE ('20120101',
                                                           'rrrrmmdd'
                                                  'THU'
                             AND   TRUNC (NEXT_DAY (TO_DATE ('20120101',
                                                             'rrrrmmdd'
                                                    'THU'
                                 + 7
      CONNECT BY LEVEL < 15),
     v AS
     (SELECT     t.start_date + 7 * (LEVEL - 1) start_date,
                 t.week_th + LEVEL - 1 week_th
            FROM t
      CONNECT BY LEVEL < 53),
     u AS
     (SELECT '20120501' dt
        FROM DUAL
      UNION ALL
      SELECT '20120502'
        FROM DUAL
      UNION ALL
      SELECT '20120503'
        FROM DUAL
      UNION ALL
      SELECT '20120504'
        FROM DUAL
      UNION ALL
      SELECT '20120505'
        FROM DUAL
      UNION ALL
      SELECT '20120506'
        FROM DUAL
      UNION ALL
      SELECT '20120507'
        FROM DUAL
      UNION ALL
      SELECT '20120508'
        FROM DUAL
      UNION ALL
      SELECT '20120509'
        FROM DUAL)
SELECT *
  FROM u, v
WHERE TO_DATE (u.dt, 'rrrrmmdd') BETWEEN v.start_date AND (v.start_date + 6);output:
DT     START_DATE     WEEK_TH
20120501     30/04/2012     18
20120502     30/04/2012     18
20120503     30/04/2012     18
20120504     30/04/2012     18
20120505     30/04/2012     18
20120506     30/04/2012     18
20120507     07/05/2012     19
20120508     07/05/2012     19
20120509     07/05/2012     19