plsql error invalid number

I'm getting an invalid number error when

procedure Afficher(opt int,id int) is
type emp is record(fn employees.first_name%type,
                   lname employees.last_name%type,
                   job jobs.job_title%type,
                   dep departments.department_id%type);
emp1 emp;
begin
select e1.first_name,e1.last_name,j.开发者_StackOverflowjob_title,d.department_name into emp1
from employees e1 ,jobs j,departments d where e1.employee_id= 'id' and 
e1.job_id=j.job_id and e1.department_id =d.department_id ;

      dbms_output.put_line('Name      Job       Department');
      dbms_output.put_line(emp1.fn||''|| emp1.lname||'     '
            ||emp1.job||'   '||emp1.dep);

end Afficher;

You're looking for e1.employee_id='id'; is it actually a string, or a number?

You probably want:

procedure Afficher(opt int,id int) is
type emp is record(fn employees.first_name%type,
                   lname employees.last_name%type,
                   job jobs.job_title%type,
                   dep departments.department_id%type);
emp1 emp;
begin
select e1.first_name,e1.last_name,j.job_title,d.department_name into emp1
from employees e1 ,jobs j,departments d where e1.employee_id= id and 
e1.job_id=j.job_id and e1.department_id =d.department_id ;

      dbms_output.put_line('Name      Job       Department');
      dbms_output.put_line(emp1.fn||''|| emp1.lname||'     '
            ||emp1.job||'   '||emp1.dep);

end Afficher;

I.e. no quotes around the id variable.

It's probably better to rename the variable to *emp_id* or something similar.