create or replace function avg_sal
  (dept_id employees.department_id%type)
return number;
is
  avg_salary number
begin
 select round(avg(salary), 2) into avg_salary
 from employees
 where department_id = dept_id;
 return avg_salary;
end;
/



create or replace function avg_sal
  (dept_id employees.department_id%type)
return number
is
  avg_salary number;
begin
  select round(avg(salary), 2) into avg_salary
  from employees
  where department_id = dept_id;
  return avg_salary;
end;
/

똑같은 소스인데 실행하면

위에꺼는 Encountered the symbol "IS" 라고 오류가 나고

아래꺼는 정상적으로 함수가 만들어지는데요

왜 이런 오류가 나는 건가요?