Combining two single recordset into one two column recordset

Question

Hi Forum
Assume we have three types , each 'table of'
CREATE OR REPLACE type type1 as table of number ;
CREATE OR REPLACE type type2 as table of varchar2 (255);
CREATE OR REPLACE TYPE TYPEVALUE AS OBJECT
(object_type number ,
object_value varchar2(255)
resultset1 type1 := type1() ;
resultset2 type2 := type2() ;
resultset3 typevalue := typeValue3() ;
I want to populate records of resultset3 from resultset1 and resultset2 , using resultset1 for first column of record and resultset2 for second column.
One way is to do for loop but I don't want to use this.
I need something similar to resultset3 to use it dynamically in select statement to do MINUS operation with another resultset . I think things like MULTISET, COLLECT, CAST can achieve what I want to do.
Can you please help me to have a select statement that combines two single column rowset and put into a two column recordset.
Thanks

Answer 1

Hi,
You can do something like this:
SQL> create or replace type type1 as table of number;
  2  /
Type created.
SQL> create or replace type type2 as table of varchar2(255);
  2  /
Type created.
SQL> create or replace type typevalue as object(object_type number, object_value varchar2(255));
  2  /
Type created.
SQL> create type typevalue_tab as table of typevalue;
  2  /
Type created.
SQL> ed
  1  declare
  2     resultset1 type1 := type1(1, 2, 3, 4, 5);
  3     resultset2 type2 := type2('one', 'two', 'three', 'four', 'five');
  4     resultset3 typevalue_tab;
  5  begin
  6     for l_res in (
  7        select typevalue(t1.col1, t2.col2) as col
  8        from (
  9           select column_value col1
10           , rownum rn
11           from table(cast(resultset1 as type1))
12        ) t1
13        , (
14           select column_value col2
15           , rownum rn
16           from table(cast(resultset2 as type2))
17        ) t2
18        where t1.rn = t2.rn
19     )
20     loop
21        dbms_output.put_line(
22           'Object Type:  '||l_res.col.object_type||' '||
23           'Object Value: '||l_res.col.object_value
24        );
25     end loop;
26* end;
SQL> /
Object Type:  1 Object Value: one
Object Type:  2 Object Value: two
Object Type:  3 Object Value: three
Object Type:  4 Object Value: four
Object Type:  5 Object Value: five
PL/SQL procedure successfully completed.All the work here is done in SQL so it should work similarly if you have these things defined as nested table columns in the database.
However, there is a caveat here: the lines highlighted in bold above are defining an arbitrary ordering for the nested table elements using rownum, as there is no concept of ordering within a nested table. You should change this part of the query to whatever makes sense in your environment, otherwise this solution cannot be guaranteed to be correct. Another option would be to use VARRAYs, as they will retain the order of elements.
cheers,
Anthony