Oracle – How to grant to stored procedure, privileges to select from a different schema

In addition to what Mark Brady said, another dynamic SQL option is to use a REF CURSOR. Since your sample code includes a cursor this would be the most relevant.

PROCEDURE select_from_schema( the_schema VARCHAR2)
IS
  TYPE my_cursor_type IS REF CURSOR;
  my_cursor  my_cursor_type;
BEGIN
  OPEN my_cursor FOR 'SELECT my_field FROM '||the_schema||'.my_table';

  -- Do your FETCHes just as with a normal cursor

  CLOSE my_cursor;
END;

In SQL Plus:

SQL> create procedure myproc (prc out sys_refcursor)
  2  is
  3  begin
  4     open prc for select * from emp;
  5  end;
  6  /

Procedure created.

SQL> var rc refcursor
SQL> execute myproc(:rc)

PL/SQL procedure successfully completed.

SQL> print rc

     EMPNO ENAME      JOB              MGR HIREDATE           SAL       COMM     DEPTNO
---------- ---------- --------- ---------- ----------- ---------- ---------- ----------
      7839 KING       PRESIDENT            17-NOV-1981       4999                    10
      7698 BLAKE      MANAGER         7839 01-MAY-1981       2849                    30
      7782 CLARKE     MANAGER         7839 09-JUN-1981       2449                    10
      7566 JONES      MANAGER         7839 02-APR-1981       2974                    20
      7788 SCOTT      ANALYST         7566 09-DEC-1982       2999                    20
      7902 FORD       ANALYST         7566 03-DEC-1981       2999                    20
      7369 SMITHY     CLERK           7902 17-DEC-1980       9988         11         20
      7499 ALLEN      SALESMAN        7698 20-FEB-1981       1599       3009         30
      7521 WARDS      SALESMAN        7698 22-FEB-1981       1249        551         30
      7654 MARTIN     SALESMAN        7698 28-SEP-1981       1249       1400         30
      7844 TURNER     SALESMAN        7698 08-SEP-1981       1499          0         30
      7876 ADAMS      CLERK           7788 12-JAN-1983       1099                    20
      7900 JAMES      CLERK           7698 03-DEC-1981        949                    30
      7934 MILLER     CLERK           7782 23-JAN-1982       1299                    10
      6668 Umberto    CLERK           7566 11-JUN-2009      19999          0         10
      9567 ALLBRIGHT  ANALYST         7788 02-JUN-2009      76999         24         10