Restricting on a cursor result

Question

Task:
1. I would like to make reports for a system.
2. I want to make the reports with an out sys_refcursor
3. I want to pass in some cursor with ids, to restrict report.
So here's the code I got so far:
procedure customer_status_distribution(c_universe sys_refcursor,
t_result out sys_refcursor) is
v_table_of_number table_of_number;
begin
fetch c_universe bulk collect
into v_table_of_number;
open t_result for with a as(
select column_value column_value
from table(cast(v_table_of_number as table_of_number)))
select t.alder, count(*)
from customer_aggregation t
where customer_id in(select column_value from a)
group by t.alder;
end;
c_universe is containing just numbers of course.
The problem with this is that it doesn't use the index on customer_aggregation.customer_id column.
I can add /*+RULE*/ and it uses the index, but I do not want that, since the actual reports are quite more complex, and will use different technuiqes for optimizing.
exists() clause does not use index.
/*+ index(customer_aggregation name_of_index)*/ doesn't do it.
Am I going about this the wrong way? Any ideas?

Answer 1

Following code:
fetch c_universe bulk collect
into v_table_of_number;
open t_result for
select t.alder, count(*)
from customer_aggregation t
where exists(select * from table(cast(v_table_of_number as table_of_number)) where column_value = t.customer_id)
group by t.alder;
gives:
SELECT STATEMENT      12176732          
SORT GROUP BY     12176732     1     9
NESTED LOOPS SEMI     12176729     1     9
TABLE ACCESS FULL -> CUSTOMER_AGGREGATION     1457     1521909     13697181
COLLECTION ITERATOR PICKLER FETCH          
Rewrite using in:
fetch c_universe bulk collect
into v_table_of_number;
open t_result for
select t.alder, count(*)
from customer_aggregation t
where t.customer_id in(select column_value from table(cast(v_table_of_number as table_of_number)))
group by t.alder;
gives:
SELECT STATEMENT      12176732          
SORT GROUP BY     12176732     1     9
NESTED LOOPS SEMI     12176729     1     9
TABLE ACCESS FULL -> CUSTOMER_AGGREGATION     1457     1521909     13697181
COLLECTION ITERATOR PICKLER FETCH               
Rewrite to use hints and "in":
fetch c_universe bulk collect
into v_table_of_number;
open t_result for
select /*+index(t PK_AGGR_CUSTOMER_ID)*/ t.alder, count(*)
from customer_aggregation t
where t.customer_id in(select column_value from table(cast(v_table_of_number as table_of_number)))
group by t.alder;
end;
gives:
SELECT STATEMENT      12211234          
SORT GROUP BY     12211234     1     9
NESTED LOOPS SEMI     12211231     1     9
TABLE ACCESS BY INDEX ROWID -> CUSTOMER_AGGREGATION     35959     1521909     13697181
INDEX FULL SCAN -> PK_AGGR_CUSTOMER_ID     11354     1521909     
COLLECTION ITERATOR PICKLER FETCH               
Rewrite using index hint and "exists":
fetch c_universe bulk collect
into v_table_of_number;
open t_result for
select /*+index(t PK_AGGR_CUSTOMER_ID)*/ t.alder, count(*)
from customer_aggregation t
where exists(select column_value from table(cast(v_table_of_number as table_of_number)) where column_value = t.customer_id)
group by t.alder;
gives:
SELECT STATEMENT      12211234          
SORT GROUP BY     12211234     1     9
NESTED LOOPS SEMI     12211231     1     9
TABLE ACCESS BY INDEX ROWID -> CUSTOMER_AGGREGATION     35959     1521909     13697181
INDEX FULL SCAN -> PK_AGGR_CUSTOMER_ID     11354     1521909     
COLLECTION ITERATOR PICKLER FETCH               
Finally, what I want is (explain plan wise):
the code posted using a tmp_numbers table:
which gives:
SELECT STATEMENT      10          
SORT GROUP BY     10     1     22
TABLE ACCESS BY INDEX ROWID -> CUSTOMER_AGGREGATION     3     1     9
NESTED LOOPS      8     1     22
SORT UNIQUE               
TABLE ACCESS FULL -> TMP_NUMBERS     2     1     13
INDEX RANGE SCAN -> PK_AGGR_CUSTOMER_ID (1)     2     1     
Suggestions?