Compilation pl/sql error

Question

create or replace procedure proc_test(v_empno in number
                           ,v_ref_cursor out sys_refcursor
) is
function get_dept_name(p_department_id number)
return varchar2
is
v_dept_name varchar2(100);
begin
select department_name into v_dept_name
from departments
where department_id = p_department_id;
return v_dept_name;
end;
begin
open v_ref_cursor for
select e.last_name,get_dept_name(e.department_id)
from employees e
where e.employee_id = v_empno;
end;
This function give following
LINE/COL ERROR
18/2     PL/SQL: SQL Statement ignored
18/21    PL/SQL: ORA-00904: : invalid identifier
18/21    PLS-00231: function 'GET_DEPT_NAME' may not be used in SQL
Can you please clarify.

Answer 1

The function must be visible to SQL:
SQL> create or replace function get_dept_name(p_department_id varchar2)
  2  return varchar2
  3  is
  4    v_dept_name varchar2(100);
  5  begin
  6    select dummy into v_dept_name
  7    from   dual
  8    where dummy = p_department_id;
  9    --
10    return v_dept_name;
11    --
12  end;
13  /
Function created.
SQL>
SQL> create or replace procedure proc_test
  2  ( v_empno in varchar2
  3  , v_ref_cursor out sys_refcursor
  4  )
  5  is
  6  begin
  7   open v_ref_cursor for
  8   select e.dummy
  9   ,      get_dept_name(e.dummy)
10   from   dual e
11   where  e.dummy = v_empno;
12  end;
13  /
Procedure created.
SQL> set autoprint on
SQL> var rc refcursor;
SQL> exec proc_test('X', :rc)
PL/SQL procedure successfully completed.
D
GET_DEPT_NAME(E.DUMMY)
X
X
1 row selected.
Ofcourse you'd encapsulate all this in a package.