Trouble writing Query for Pivoting data from a table

Question

I am having a little trouble writing a query for converting the below table data into a pivot data. I am trying to write a query for which if I give a single valid report_week date as input it should give me the data for that week and also provide two extra columns, one which gives the data of last week for the same countries and the second column which gives the difference of numbers in both the columns(i.e. COUNT - COUNT_LAST_WEEK).
REPORT_WEEK     DIVISION     COUNT
9/26/2009     country1     81
9/26/2009     country2     97
9/26/2009     country3     12
9/26/2009     country4     26
9/26/2009     country5     101
10/3/2009     country1     85
10/3/2009     country2     98
10/3/2009     country3     10
10/3/2009     country4     24
10/3/2009     country5     101
10/10/2009     country1     84
10/10/2009     country2     98
10/10/2009     country3     10
10/10/2009     country4     25
10/10/2009     country5     102
For example, if I give input as 10/10/2009, the output should be as give below.
REPORT_WEEK     DIVISION     COUNT     COUNT_LAST_WEEK     DIFFERENCE
10/10/2009     country1     84     85     -1
10/10/2009     country2     98     98     0
10/10/2009     country3     10     10     0
10/10/2009     country4     25     24     1
10/10/2009     country5     102     101     1
For example, if I give input as 10/3/2009, the output should be as give below.
REPORT_WEEK     DIVISION     COUNT     COUNT_LAST_WEEK     DIFFERENCE
10/3/2009     country1     85     81     4
10/3/2009     country2     98     97     1
10/3/2009     country3     10     12     -2
10/3/2009     country4     24     26     -2
10/3/2009     country5     101     101     0
Can anyone please shed some light on Query building for the above scenarios.
Thank you
SKP
Edited by: user11343284 on Oct 10, 2009 7:53 AM
Edited by: user11343284 on Oct 10, 2009 8:28 AM

Answer 1

I assume there is no gap in report weeks. If so:
SQL> variable report_week varchar2(10)
SQL> exec :report_week := '10/10/2009'
PL/SQL procedure successfully completed.
with t as (
           select to_date('9/26/2009','mm/dd/yyyy') report_week,'country1' division,81 cnt from dual union all
           select to_date('9/26/2009','mm/dd/yyyy'),'country2',97 from dual union all
           select to_date('9/26/2009','mm/dd/yyyy'),'country3',12 from dual union all
           select to_date('9/26/2009','mm/dd/yyyy'),'country4',26 from dual union all
           select to_date('9/26/2009','mm/dd/yyyy'),'country5',101 from dual union all
           select to_date('10/3/2009','mm/dd/yyyy'),'country1',85 from dual union all
           select to_date('10/3/2009','mm/dd/yyyy'),'country2',98 from dual union all
           select to_date('10/3/2009','mm/dd/yyyy'),'country3',10 from dual union all
           select to_date('10/3/2009','mm/dd/yyyy'),'country4',24 from dual union all
           select to_date('10/3/2009','mm/dd/yyyy'),'country5',101 from dual union all
           select to_date('10/10/2009','mm/dd/yyyy'),'country1',84 from dual union all
           select to_date('10/10/2009','mm/dd/yyyy'),'country2',98 from dual union all
           select to_date('10/10/2009','mm/dd/yyyy'),'country3',10 from dual union all
           select to_date('10/10/2009','mm/dd/yyyy'),'country4',25 from dual union all
           select to_date('10/10/2009','mm/dd/yyyy'),'country5',102 from dual
select  max(report_week) report_week,
        division,
        max(cnt) keep(dense_rank last order by report_week) cnt_this_week,
        max(cnt) keep(dense_rank first order by report_week) cnt_last_week,
        max(cnt) keep(dense_rank last order by report_week) - max(cnt) keep(dense_rank first order by report_week) difference
  from  t
  where report_week in (to_date(:report_week,'mm/dd/yyyy'),to_date(:report_week,'mm/dd/yyyy') - 7)
  group by division
  order by division
REPORT_WE DIVISION CNT_THIS_WEEK CNT_LAST_WEEK DIFFERENCE
10-OCT-09 country1            84            85         -1
10-OCT-09 country2            98            98          0
10-OCT-09 country3            10            10          0
10-OCT-09 country4            25            24          1
10-OCT-09 country5           102           101          1
SQL> exec :report_week := '10/3/2009'
PL/SQL procedure successfully completed.
SQL> /
REPORT_WE DIVISION CNT_THIS_WEEK CNT_LAST_WEEK DIFFERENCE
03-OCT-09 country1            85            81          4
03-OCT-09 country2            98            97          1
03-OCT-09 country3            10            12         -2
03-OCT-09 country4            24            26         -2
03-OCT-09 country5           101           101          0
SQL> SY.