为什么可以'；在plsql中，我是否在一个sql命令中使用current of和return to？

我尝试使用游标和UPDATESQL命令更新图书的价格。我在一个更新命令中使用了current of和return to，出现错误：ORA-00933:SQL命令未正确结束

我不得不改变我的更新，我写了id=id_zet。它修复了它，但我不明白，为什么下面的代码是错误的。因此，我的问题是：为什么我不能在plsql中的一个sql命令中使用current of和returning to

  SET serveroutput ON;
  DECLARE

  CURSOR books IS 
  SELECT title, id_publisher
    FROM book
    FOR UPDATE OF price;
  price book.price%TYPE;
  id_zet publisher.id%TYPE;
  BEGIN
    SELECT id INTO id_zet FROM publisher WHERE company_name = 'Zet';
    FOR k IN books LOOP
      IF k.id_publisher = id_zet THEN
        UPDATE book SET book.price = 1.1*book.price WHERE CURRENT OF books RETURNING book.price INTO price;
      ELSE
        UPDATE book SET book.price = 1.05*book.price WHERE CURRENT OF books RETURNING book.price INTO price;
      END IF;
      DBMS_OUTPUT.PUT_LINE(k.title || ' ' || price);
    END LOOP;

  END;

---

据我所知，唯一的原因是Oracle没有实现它。在你的情况下，这很容易解决

DECLARE

    CURSOR books IS 
      SELECT title, id_publisher, price
        FROM book
        FOR UPDATE OF price;
      price book.price%TYPE;
      id_zet publisher.id%TYPE;
BEGIN
    SELECT id INTO id_zet FROM publisher WHERE company_name = 'Zet';
    FOR k IN books LOOP
      IF k.id_publisher = id_zet THEN
        price := k.price *1.1;
      ELSE
        price := k.price *1.05;
      END IF;
      UPDATE book 
       SET book.price = price 
       WHERE CURRENT OF books ;
      DBMS_OUTPUT.PUT_LINE(k.title || ' ' || price);
    END LOOP;
 END;

在这样的游标循环中逐行更新并不是一种特别有效的工作方式

你可以换成

  UPDATE book 
  SET book.price = price * decode(id, id_zet, 1.1, 1.05);

---

这个能用吗？根据甲骨文的说法，它的做法完全相同：

CURSOR books IS 
 SELECT title, id_publisher, ROWID as aROW
   FROM book
   FOR UPDATE OF price;
 price book.price%TYPE;
 id_zet publisher.id%TYPE;

BEGIN
   SELECT id INTO id_zet FROM publisher WHERE company_name = 'Zet';
   FOR k IN books LOOP
     IF k.id_publisher = id_zet THEN
       UPDATE book SET book.price = 1.1*book.price WHERE ROWID = k.aROW RETURNING bookprice INTO price;
     ELSE
       UPDATE book SET book.price = 1.05*book.price WHERE ROWID = k.aROW RETURNING book.price INTO price;
     END IF;
     DBMS_OUTPUT.PUT_LINE(k.title || ' ' || price);
   END LOOP;
END;

---

试图为你找到一个好的理由，但这是我能找到的全部（龙的评论）：