Passing Order By String to Cursor

Question

Hello, I am attempting to do the following:
Pass a parameter to a cursor that tells the cursor what to order by. I.e., if user clicks a date column, the tablename_datecolumn string is passed to the cursor. I thought this would have been relatively simple. However, for some reason, I can't get the following to work:
PROCEDURE my_procedure (pv_sort_code IN VARCHAR2 DEFAULT NULL)
IS
CURSOR lcur_requests (pv_sort_code IN VARCHAR2)
IS SELECT column1, column2, column3 FROM table1 WHERE column1 = item_id ORDER BY pv_sort_code ASC;
BEGIN
OPEN lcur_requests (pv_sort_code);
LOOP
FETCH lcur_requests INTO lv_value1, lv_value2, lv_value 3;
EXIT WHEN lcur_requests%NOTFOUND;
END LOOP;
END my_procedure;
When the above procedure gets called, it is aware of the pv_sort_code, which can equal any of the following:
pv_sort_code = column1, column2 -or- column3
Any ideas as to how I can accomplish the dynamic order by in the cursor?
Thanks ahead of time.

Answer 1

Here is a sample example of doing it using Dynamic SQL + Collections:
Connected to:
Oracle Database 10g Enterprise Edition Release 10.2.0.3.0 - 64bit Production
With the Partitioning, OLAP and Data Mining options
SQL> set serveroutput on
SQL> select * from my_tab;
        C1         C2
         1          5
         2          4
         3          3
         4          2
         5          1
SQL> declare
  2      sort_order1 varchar2(100) := 'c1,c2';
  3      sort_order2 varchar2(100) := 'c1 desc,c2';
  4 
  5      type my_tab_rtype is table of my_tab%rowtype index by binary_integer;
  6      my_tab_rows my_tab_rtype;
  7 
  8      str1 varchar2(32000) := 'select * from my_tab order by '||sort_order1 ;
  9      str2 varchar2(32000) := 'select * from my_tab order by '||sort_order2 ;
10  begin
11      execute immediate str1 bulk collect into my_tab_rows;
12          dbms_output.put_line('Sort Order :: ' || sort_order1);
13          dbms_output.put_line('c1 c2');
14          dbms_output.put_line('-----');
15      for i in my_tab_rows.first..my_tab_rows.last loop
16          dbms_output.put_line(my_tab_rows(i).c1 || ' ' || my_tab_rows(i).c2);
17      end loop;
18     
19      dbms_output.put_line(chr(10));
20     
21      execute immediate str2 bulk collect into my_tab_rows;
22          dbms_output.put_line('Sort Order :: ' || sort_order2);
23          dbms_output.put_line('c1 c2');
24          dbms_output.put_line('-----');
25      for i in my_tab_rows.first..my_tab_rows.last loop
26          dbms_output.put_line(my_tab_rows(i).c1 || ' ' || my_tab_rows(i).c2);
27      end loop;
28  end; 
29  /
Sort Order :: c1,c2
c1 c2
1 5
2 4
3 3
4 2
5 1
Sort Order :: c1 desc,c2
c1 c2
5 1
4 2
3 3
2 4
1 5
PL/SQL procedure successfully completed.
SQL>