编译存储过程pl sql时标识符无效

Question

这是我写的一个小测试代码。

CREATE procedure abc
IS
  tempHistoricalClassAvg integer;
begin
  select avg(e.obtainedquizscore)
  into   tempHistoricalClassAvg
  ,      e.courseid
  from   evaluation e 
  where  e.courseid = 1 
  and    e.instructorid =1 
  group by e.courseid;

  dbms_output.Put_line(tempHistoricalClassAvg);
end;

我收到编译错误

Error(5,62): PLS-00201: identifier 'E.COURSEID' must be declared

E.courseid出现在表格中，因为下面的查询工作正常

select avg(obtainedquizscore) as avgquizscore
,      courseid  
from   evaluation 
where  courseid  = 1 
and    instructorid =1 
group by courseid;

我哪里错了？ ：/