错误，而在plsql中运行简单的光标

Question

我想写一个简单的光标并打开，获取值并关闭。以下是我的光标代码。

DECLARE 
    id cur.sid%TYPE; 
    s_num cur.serial#%TYPE; 
    CURSOR cur IS 
    SELECT sid, serial# 
    FROM v$session WHERE username = 'ABC'; 
BEGIN 
    OPEN cur; 

    LOOP 
    FETCH c cur INTO id, s_num; 
    dbms_output.put_line(id || ' ' || s_num); 
    END LOOP; 

    CLOSE cur; 
END; 
/

当运行此我看到以下错误消息：

FETCH c cur INTO id, s_num; 
     * 
ERROR at line 9: 
ORA-06550: line 9, column 9: 
PLS-00103: Encountered the symbol "CUR" when expecting one of the following: 
. into bulk 
The symbol "." was substituted for "CUR" to continue. 

任何种类的方向来解决这个之一被理解。谢谢。

Answer 1

• FETCH c cur INTO id, s_num;c是多余的，删除它。

• 更改ID和s_num的认定中作为followes：
  id v$session.sid%type;
s_num v$session.serial#%type;

• 将exit when cur%notfound;作为循环的退出条件。

  DECLARE 
  CURSOR cur IS 
  SELECT sid, serial# FROM v$session where username = 'ABC'; 
  id v$session.sid%type; 
  s_num v$session.serial#%type; 
  BEGIN 
  OPEN cur; 
  LOOP 
  FETCH cur 
      INTO id, s_num; 
      exit when cur%notfound; 
      dbms_output.put_line(id || ' ' || s_num); 
  END LOOP; 
  CLOSE cur; 
  END; 
  

Answer 2

使用IMPLICIT开放和光标的获取的简化版本（参数化）

DECLARE 
    CURSOR cur(v_USER VARCHAR2) 
    IS 
    SELECT sid, serial# FROM v$session where username = v_USER; 
BEGIN 
    FOR I IN cur('ABC') 
    LOOP 
    dbms_output.put_line(I.sid || ' ' || I.serial#); 
    END LOOP; 
END;