For loop &引用；无效标识符"；循环索引的错误消息（在Oracle SQL Developer中）

为什么在运行以下行时，循环变量索引（I）会收到“invalid identifer”错误消息

SQL错误：ORA-00904：“I”：无效标识符

for i in 1..5 loop
   select Price from Orders where (ID=i);
end loop;

Orders

是一个包含两个字段的表：ID和Price

表顺序：

ID Price ------------ 1 1200 2 2250 3 1750 4 2000 5 1000 6 300 身份证价格 ------------ 1 1200 2 2250 3 1750 4 2000 5 1000 6 300

---

您可能需要将其作为匿名块运行？下面是如何使循环工作的简单示例：

DECLARE
  v_last_name VARCHAR2(2000);

BEGIN
  for i in 1..5 loop

    WITH sample_set AS (
      SELECT 1 the_number, 'frank' last_name FROM DUAL UNION ALL
      SELECT 2 the_number, 'STEVE' last_name FROM DUAL UNION ALL
      SELECT 3 the_number, 'CARL' last_name FROM DUAL UNION ALL
      SELECT 4 the_number, 'bella' last_name FROM DUAL UNION ALL
      SELECT 5 the_number, 'tank' last_name FROM DUAL)
    select last_name
    INTO   v_last_name
    from sample_set where the_number = i;

    dbms_output.put_line(v_last_name);

  end loop;
END;

你喜欢这样吗

DECLARE 
my_price long;
BEGIN
FOR I IN 1..5 loop
SELECT PRICE INTO MY_PRICE FROM ORDERS where id=i;
DBMS_OUTPUT.PUT_LINE('The price is'||' '||my_price);
end loop;
end;

---

OUTPUT
-------------------------------
The price is 1234
The price is 1235
The price is 1236
The price is 1237
The price is 1238

Statement processed.