False result of decode within max()

Question

hallo,
I'm using decode within a max() on an outer joined column. Further on, I'm outer joining multiple tables and therefore I'm executing a kind of the following query on my database (Oracle 10g R2). Finally, the query returns a false result:
Query:
select  max(t.TIME_ID), max(decode(s.promo_id, null,null, t.TIME_ID)) test_date
from    sales s
       ,times t
where   s.TIME_ID(+) = t.TIME_ID
  and   s.PROD_ID(+) = 22
  and   t.TIME_ID <= to_date('10021998', 'ddmmyyyy')
order by t.time_id;Result:
MAX(T.TIM TEST_DATE
10-FEB-98 31-JAN-98If you omit the aggregate functions, you can see that the result is not correct:
31-JAN-98 31-JAN-98
31-JAN-98 31-JAN-98
01-FEB-98
02-FEB-98 02-FEB-98
03-FEB-98 03-FEB-98
03-FEB-98 03-FEB-98
04-FEB-98
05-FEB-98
06-FEB-98
07-FEB-98 07-FEB-98
08-FEB-98 08-FEB-98
09-FEB-98
10-FEB-98 10-FEB-98
10-FEB-98 10-FEB-98Can anyone help me?
Thanks

Answer 1

Martin_H. wrote:
For instance, how do you write this query in ANSI syntax without adding the column PROD_ID into the on clause and avoide breaking the outer join:
select  t.TIME_ID, s.time_id
from    times t
,sales s
where   t.time_id = s.time_id(+)
and   s.PROD_ID(+) = 22If you use the ANSI syntax and exclude a column from the on clause it will break the outer join. I personally exclude any column from the on clause, which definitely stands not for a join column and therefore I do not know how to use the ANSI syntax for outer joins without breaking them.
select  t.TIME_ID, s.time_id
from    times t
left outer join sales s on (t.time_id) = ((s.time_id))
where   s.PROD_ID = 22  // how to tell oracle to outer join s.prod_id within the where clauseRegards,
Martin
Edited by: Martin_H. on 30-Jul-2010 02:01Ah I see your problem. But you are restricting yourself by saying that the condition should not belong into the ON clause. This would be the usual solution.
However this is not a technical restriction because of the ansi syntax but a restriction that you impose upon you by yourself.
how to tell oracle to outer join s.prod_id
select  t.TIME_ID, s.time_id
from    times t
left outer join sales s on t.time_id = s.time_id and s.PROD_ID = 22I think this is abosolutly ok to write it like that. From a logic point of view it means:
Find all times and show me if there had been sales for product 22.
what should also work is
how to tell oracle to outer join s.prod_id within the where clause
select  t.TIME_ID, s.time_id
from  times t
left outer join sales s on t.time_id = s.time_id
where (s.PROD_ID = 22 or s.PROD_ID is null)It means:
Find all times and show me if there had been sales
I only want to see sales for product 22.
Edited by: Sven W. on Jul 30, 2010 11:09 AM