SQL Challenge - Returning count=0 for non-existing values

Question

Hello there,
I have a question about our requirement and an SQL query. I have posted this to some email groups but got no answer yet.
Here is the test case:
SQL> conn ...
Connected.
-- create the pattern table and populate
SQL> create table pattern(id number, keydescription varchar2(50));
Table created.
SQL> insert into pattern values(1,'hata1');
1 row created.
SQL> insert into pattern values(2,'hata2');
1 row created.
SQL> insert into pattern values(3,'hata3');
1 row created.
SQL> insert into pattern values(4,'hata4');
1 row created.
SQL> insert into pattern values(5,'hata5');
1 row created.
SQL> select * from pattern;
ID KEYDESCRIPTION
1 hata1
2 hata2
3 hata3
4 hata4
5 hata5
SQL> commit;
Commit complete.
-- create the messagetrack and populate
SQL> create table messagetrack(pattern_id number, realdate date);
Table created.
SQL> insert into messagetrack values(1,to_date('26/08/2007 13:00:00','dd/mm/yyyy hh24:MI:ss'));
1 row created.
SQL> insert into messagetrack values(1,to_date('26/08/2007 13:05:00','dd/mm/yyyy hh24:MI:ss'));
1 row created.
SQL> insert into messagetrack values(2,to_date('26/08/2007 13:15:00','dd/mm/yyyy hh24:MI:ss'));
1 row created.
SQL> insert into messagetrack values(3,to_date('26/08/2007 14:15:00','dd/mm/yyyy hh24:MI:ss'));
1 row created.
SQL> insert into messagetrack values(4,to_date('26/08/2007 15:15:00','dd/mm/yyyy hh24:MI:ss'));
1 row created.
SQL> insert into messagetrack values(1,to_date('26/08/2007 15:15:00','dd/mm/yyyy hh24:MI:ss'));
1 row created.
SQL> commit;
Commit complete.
SQL> select * from messagetrack;
PATTERN_ID REALDATE
1 26-AUG-07
1 26-AUG-07
2 26-AUG-07
3 26-AUG-07
4 26-AUG-07
1 26-AUG-07
6 rows selected.
Now, we have this simple query:
SQL> select p.KeyDescription as rptBase , to_char( mt.realdate,'dd') as P1 , to_char(mt.realdate,'HH24') as P2, count(*) as countX
2 from messageTrack mt, Pattern p
3 Where mt.realDate >= to_date('26/08/2007 13:00:00','dd/MM/yyyy hh24:MI:ss')
4 and mt.realDate <= to_date('27/08/2007 20:00:00','dd/MM/yyyy hh24:MI:ss')
5 and mt.pattern_id=p.id
6 group by p.KeyDescription, to_char(mt.realdate,'dd'), to_char( mt.realdate,'HH24')
7 order by p.KeyDescription, to_char(mt.realdate,'dd'), to_char(mt.realdate,'HH24');
RPTBASE P1 P2 COUNTX
hata1 26 13 2
hata1 26 15 1
hata2 26 13 1
hata3 26 14 1
hata4 26 15 1
But the result we need should contain the pattern values(hata1, hata2, hata3 and hata4) for each time interval(hour) although there are might be no records of some patterns for some hours.
The result for our test case should look like this:
RPTBASE P1 P2 COUNTX
hata1 26 13 2
hata1 26 14 0
hata1 26 15 0
hata2 26 13 1
hata2 26 14 0
hata2 26 15 0
hata3 26 13 0
hata3 26 14 1
hata3 26 15 0
hata4 26 13 0
hata4 26 14 0
hata4 26 15 1
Our version is 10.2.0.2
On my discussions some said model clause may be used, but i don't know model clause much and can't imagine how to use.
You can download the test case code above to reproduce from:
http://www.bhatipoglu.com/files/query1.txt
You can see the output above more clearly(monospace font) on:
http://www.bhatipoglu.com/files/query1_output.txt
Additionally, I want to state that, in the resulting table, we don't want all the patterns(hata1, hata2, hata3, hata4 and hata5). We just want the ones that exists on messageTrack table(hata1, hata2, hata3 and hata4) as you see on the result.
Thanks in advance.

Answer 1

Here is an attempt with the Model Clause:
Edit: I should mention that I created a view out of your original query.
SELECT rptbase
      ,day
      ,hour
      ,countx
FROM demoV
  MODEL
    DIMENSION BY (rptbase, day, hour)
    MEASURES (countx)
      RULES(countx[
                    FOR rptbase IN (SELECT rptbase
                                    FROM demoV)
                    ,FOR day IN   (SELECT day
                                    FROM demoV)
                    ,FOR hour FROM 13 to 15 INCREMENT 1
                    ] =
                    NVL(countx[CV(rptbase),CV(day),CV(hour)],0)
            order by 1,2,3;Which produces the following
RPTBASE                                    DAY                 HOUR               COUNTX                
hata1                                              26                     13                     2                     
hata1                                              26                     14                     0                     
hata1                                              26                     15                     1                     
hata2                                              26                     13                     1                     
hata2                                              26                     14                     0                     
hata2                                              26                     15                     0                     
hata3                                              26                     13                     0                     
hata3                                              26                     14                     1                     
hata3                                              26                     15                     0                     
hata4                                              26                     13                     0                     
hata4                                              26                     14                     0                     
hata4                                              26                     15                     1               Note my Hata1 26 15 has a countx of 1 (I believe that this is correct and that your sample result is incorrect, if this is not the case, please explain why it should be 0)
Message was edited by:
JS1