Discoverer parameter issue

Question

I need to use the same pair of parameters for a query composed by "union all" with three independent queries.
Consider the following example:
create table docs(supplier varchar2(20), doc_date date, doc_num varchar2(10), amount number);
insert into docs values ('Alfonso', sysdate-3, 'doc00001', 100);
insert into docs values ('Alfonso', sysdate-3, 'doc00002', 20);
insert into docs values ('Alfonso', sysdate-2, 'doc00003', 50);
insert into docs values ('Alfonso', sysdate-2, 'doc00004', 10);
insert into docs values ('Alfonso', sysdate-1, 'doc00005', 80);
insert into docs values ('Alfonso', sysdate-1, 'doc00006', 20);
insert into docs values ('Alfonso', sysdate, 'doc00007', 40);
insert into docs values ('Alfonso', sysdate, 'doc00008', 50);
commit;
with calendar as (select (sysdate-3) date_from, (sysdate-1) date_to from dual)
select d.supplier, max(trunc(c.date_from)) doc_date, max('suma al '||c.date_from) document, sum(d.amount) amount
from docs d, calendar c
where d.doc_date <= c.date_from group by d.supplier
union all
select d.supplier, trunc(d.doc_date), d.doc_num, d.amount
from docs d, calendar c
where d.doc_date between c.date_from and c.date_to
union all
select d.supplier, max(trunc(c.date_to)), max('suma al '||c.date_to), sum(d.amount)
from docs d, calendar c
where d.doc_date <= c.date_to group by d.supplier;
SUPPLIER DOC_DATE DOCUMENT AMOUNT
Alfonso 15/12/09 suma al 15/12/09 120
Alfonso 16/12/09 doc00003 50
Alfonso 16/12/09 doc00004 10
Alfonso 17/12/09 doc00005 80
Alfonso 17/12/09 doc00006 20
Alfonso 17/12/09 suma al 17/12/09 280
In the example, I use the static values (sysdate-3) and (sysdate-1)... these values were that I want to pass to Discoverer
But in Discoverer, I only can use a parameter with conditions (i.e. the where clause) in a folder
Any ideas ?
Thanks in advance
Alfonso

Answer 1

Hi,
Yes, the query should have a group by as shown below. Of course, you never enter a group by when you are setting up a query in a Discoverer workbook, you just add the supplier, create the calculations and condition, and add the sort order.
select supplier, max(least(:date_to, doc_date)),
max(case when doc_num 'summary' and doc_date <= :date_from then 'suma al '||:date_from
when doc_num <> 'summary' and doc_date <= :date_to doc_num
when doc_num = 'summary' then 'suma al '||:date_to
end),
sum(amount)
from supplier_folder
group by supplier
where doc_date <= :date_to
order by max(least(:date_to, doc_date))
You don't need to do the summation in the view, you can do it all in the workbook as shown above. The view/custom folder only needs to return all the records you need in the workbook, it doesn't need any group by, so it can just union all the records together as shown in my first query. You can do the summing in the workbook after the parameters have been applied, therefore the view does not need to contain any parameters or any group by.
If you really do want to put parameters in a view then you need to use session parameters, implemented by using database contexts. See the LearnDiscoverer blog for more details.
Rod West