How to iterate over a date range in PL/SQL

Question

I need to write a report that generates summary totals against a table with date ranges for each record.

table data:
option   start_date   end_date
opt1              


        

Answer 1

You will need some sort of calendar to loop through a range of date. I have built one using the connect by level trick. You can then join the calendar with your data (cross join since you want a row even when there is no option for that day):

SQL> WITH calendar AS (
  2     SELECT to_date(:begin_date, 'mm/dd/yyyy') + ROWNUM - 1 c_date
  3       FROM dual
  4      CONNECT BY LEVEL <= to_date(:end_date, 'mm/dd/yyyy') 
                             - to_date(:begin_date, 'mm/dd/yyyy') + 1
  5  )
  6  SELECT c_date "date", d_option "option", COUNT(one_day)
  7    FROM (SELECT c.c_date, d.d_option,
  8                  CASE
  9                     WHEN c.c_date BETWEEN d.start_date AND d.end_date THEN
 10                      1
 11                  END one_day
 12             FROM DATA d, calendar c)
 13   GROUP BY c_date, d_option
 14  ORDER BY 1,2;

date        option COUNT(ONE_DAY)
----------- ------ --------------
01/06/2009  opt1                0
01/06/2009  opt2                0
02/06/2009  opt1                0
02/06/2009  opt2                0
03/06/2009  opt1                1
03/06/2009  opt2                0
04/06/2009  opt1                1
04/06/2009  opt2                0
05/06/2009  opt1                1
05/06/2009  opt2                1
06/06/2009  opt1                1
06/06/2009  opt2                1

12 rows selected