Get the starting date and end date of all weeks of a given month and year

Question

hey Guys so far I have this.. but I am having difficulty limiting it by month. I am using Oracle 11 release 1
Select year, week, next_day( to_date( '04-jan-' || year, 'dd-mon-yyyy' ) + (week-2)*7, 'sun' ) as weekStartDate,
next_day( to_date( '04-jan-' || year, 'dd-mon-yyyy' ) + (week-2)*7, 'sun' ) +6 as weekEndDate
from (Select '2012' year, rownum week from all_objects where rownum<=5)
Thanks in advance
Edited by: Aj05 on Jan 12, 2012 7:42 AM

Answer 1

First you need to define week starting day. If, for example it is Monday:
TRUNC(TRUNC(&dt,'YYYY') -1,'IW')is first Monday of the year. Then:
SELECT TRUNC(TRUNC(&dt,'YYYY') -1,'IW') + (LEVEL - 1) * 7 week_start_date
  FROM  DUAL
  CONNECT BY LEVEL <= 53
/will give start dates of all weeks within &dt year. And:
WITH t AS (
           SELECT TRUNC(TRUNC(&dt,'YYYY') -1,'IW') + (LEVEL - 1) * 7 week_start_date
            FROM  DUAL
            CONNECT BY LEVEL <= 53
SELECT  week_start_date,
        week_start_date + 6 week_end_date
  FROM  t
  WHERE week_start_date > TRUNC(&dt,'MM')
    AND week_start_date < ADD_MONTHS(TRUNC(&dt,'MM'),1)
/will give you week start/end dates within &dt year and month. For example:
SQL> DEFINE dt="DATE '2012-03-17'"
SQL> WITH t AS (
  2             SELECT TRUNC(TRUNC(&dt,'YYYY') -1,'IW') + (LEVEL - 1) * 7 week_start_date
  3              FROM  DUAL
  4              CONNECT BY LEVEL <= 53
  5            )
  6  SELECT  week_start_date,
  7          week_start_date + 6 week_end_date
  8    FROM  t
  9    WHERE week_start_date > TRUNC(&dt,'MM')
10      AND week_start_date < ADD_MONTHS(TRUNC(&dt,'MM'),1)
11  /
old   2:            SELECT TRUNC(TRUNC(&dt,'YYYY') -1,'IW') + (LEVEL - 1) * 7 week_start_date
new   2:            SELECT TRUNC(TRUNC(DATE '2012-03-17','YYYY') -1,'IW') + (LEVEL - 1) * 7 week_start_date
old   9:   WHERE week_start_date > TRUNC(&dt,'MM')
new   9:   WHERE week_start_date > TRUNC(DATE '2012-03-17','MM')
old  10:     AND week_start_date < ADD_MONTHS(TRUNC(&dt,'MM'),1)
new  10:     AND week_start_date < ADD_MONTHS(TRUNC(DATE '2012-03-17','MM'),1)
WEEK_STAR WEEK_END_
05-MAR-12 11-MAR-12
12-MAR-12 18-MAR-12
19-MAR-12 25-MAR-12
26-MAR-12 01-APR-12
SQL> SY.