DECLARE 
TYPE t_line_cursor IS REF CURSOR;
l_cursor   	t_line_cursor;
sql_stmt VARCHAR2(1000);

BEGIN
sql_stmt := 'Select 'X' from DUAL';
OPEN l_cursor for sql_stmt;
END;
/


DECLARE 
TYPE t_line_cursor IS REF CURSOR;
l_cursor   	t_line_cursor;
BEGIN
OPEN l_cursor for Select 'X' from DUAL;
END;
/

CREATE TABLE P1 (COL1 VARCHAR2(100));

INSERT ALL  
INTO P1 VALUES (1)
INTO P1 VALUES (2)
INTO P1 VALUES (3)
INTO P1 VALUES (4)
INTO P1 VALUES (5)
INTO P1 VALUES (6)
INTO P1 VALUES (7)
SELECT * FROM DUAL
/

COMMIT;



DECLARE
  pi_val VARCHAR2(100) := '1,2,3,5';
  TYPE t_line_cursor IS REF CURSOR;
  l_cursor   	t_line_cursor;
BEGIN
	OPEN l_cursor for SELECT * from P1 WHERE COL1 IN (pi_val);
END;
/

SQL> var maliste varchar2(100)
SQL> exec :maliste := '5,11,13,22,23,31,44,45'

PL/SQL procedure successfully completed.

SQL> select id, valeur
  2  from t
  3  where id IN (
  4    select substr(:maliste,
  5                  instr(','||:maliste||',', ',', 1, rn),
  6                  instr(','||:maliste||',', ',', 1, rn+1)
  7                  - instr(','||:maliste||',', ',', 1, rn) - 1) value
  8    from (select rownum rn from dual 
  9          connect by level 
 10                       <= length(:maliste)-length(replace(:maliste,',',''))+1)
 11    )
 12  order by id
 13  /
        ID VALEUR
---------- ------------------------------
         5 SYSTEM
        11 OUTLN
        22 MICHEL
        23 OPS$MCADOT101205
        31 SCOTT

5 rows selected.

  1  DECLARE
  2    pi_val VARCHAR2(100) := ',1,2,3,5,';
  3    TYPE t_line_cursor IS REF CURSOR;
  4    l_cursor    t_line_cursor;
  5  BEGIN
  6    for rec in (SELECT * from P1 WHERE instr(pi_val, ','||COL1||',')>0) loop
  7      dbms_output.put_line(rec.col1);
  8    end loop;
  9* END;
SQL> /
1
2
3
5

PL/SQL procedure successfully completed.