oracle plsql儲存過程除錯出錯_PLS-00361

SQL> create or replace procedure p_query_all_question(o_result sys_refcursor)
  2  --線上答疑顯示所有問題
  3 
  4  --顯示的列：學段，科目,題目內容,提問者，瀏覽數，狀態，更新時間
  5  --涉及到的表：問題資訊,問題統計資訊,學段科目資訊
  6  as
  7  v_sqlstr varchar2(4000);
  8  begin
  9  v_sqlstr:='select
 10                  xk.teacherstage,--學段
 11                  xk.subjectname,--科目
 12                  qi.question_title,--題目內容
 13                  qi.question_id,--提問者
 14                  qt.browse_count,--瀏覽數
 15                  qi.question_status,--狀態
 16                  qt.lastest_update_time --更新時間
 17            from Q_QUESTIONINFO qi,Q_QUESTION_STAT qs,E_SUBJECTINFO xk
 18            where qi.questionid=qs.questionid and qi.subject_id=xk.subject_id
 19            ';
 20  open o_result for v_sqlstr;
 21           
 22  end;
 23  /

Warning: Procedure created with compilation errors.

SQL> show err
Errors for PROCEDURE P_QUERY_ALL_QUESTION:

LINE/COL ERROR
-------- -----------------------------------------------------------------
20/1     PL/SQL: Statement ignored
20/6     PLS-00361: IN cursor 'O_RESULT' cannot be OPEN'ed