sql - 使用编译错误创建的触发器

Question

我编写了这个触发器来在进行新购买时将数据库中的顶级客户折扣 10%:

CREATE or REPLACE TRIGGER CLIENT_DISCOUNT
  BEFORE INSERT
  ON PURCHASE
  FOR EACH ROW
DECLARE
  CLIENTNO  NUMBER(5);
BEGIN
  SELECT (SELECT CLIENT.CLIENTNO, CLIENT.CNAME, TOTALS.TOTAL FROM CLIENT, 
    (SELECT CLIENTNO, SUM(AMOUNT) AS TOTAL FROM PURCHASE GROUP BY CLIENTNO) TOTALS WHERE CLIENT.CLIENTNO = TOTALS.CLIENTNO  AND ROWNUM <= 1 ORDER BY TOTALS.TOTAL DESC).CLIENTNO INTO CLIENTNO;
  IF :NEW.CLIENTNO = CLIENTNO THEN
    :NEW.AMOUNT = (:NEW.AMOUNT * 0.1);
  END IF;
END;

但是，当我执行此语句时，我收到此消息:

Warning: Trigger created with compilation errors.

有人可以告诉我我做错了什么吗？

谢谢，
亚历克斯。

更新 - 错误:

Errors for TRIGGER CLIENT_DISCOUNT:

LINE/COL
--------------------------------------------------------------------------------
ERROR
--------------------------------------------------------------------------------
4/3
PL/SQL: SQL Statement ignored

5/141
PL/SQL: ORA-00907: missing right parenthesis

7/17
PLS-00103: Encountered the symbol "=" when expecting one of the following:


LINE/COL
--------------------------------------------------------------------------------
ERROR
--------------------------------------------------------------------------------
   := . ( @ % ; indicator

8/3
PLS-00103: Encountered the symbol "END"

解决方案:

CREATE or REPLACE TRIGGER CLIENT_DISCOUNT
    BEFORE INSERT
    ON PURCHASE
    FOR EACH ROW
DECLARE
    vCLIENTNO  NUMBER(5);
BEGIN
    SELECT TOPCLIENT.CLIENTNO INTO vCLIENTNO FROM (SELECT CLIENT.CLIENTNO, CLIENT.CNAME, TOTALS.TOTAL FROM CLIENT, (SELECT CLIENTNO, SUM(AMOUNT) AS TOTAL FROM PURCHASE GROUP BY CLIENTNO) TOTALS WHERE CLIENT.CLIENTNO = TOTALS.CLIENTNO  AND ROWNUM <= 1 ORDER BY TOTALS.TOTAL DESC) TOPCLIENT;
    IF :NEW.CLIENTNO = vCLIENTNO THEN
        :NEW.AMOUNT := (:NEW.AMOUNT * 0.9);
    END IF;
END;
/

Answer 1

我手头没有你的 table ，所以我不能保证我已经找到了你所有的错误。但是，我可以说以下几点:

我不相信你能做到SELECT (....).CLIENTNO .试试 SELECT x.CLIENTNO FROM (....) x反而。

您的最外层 SELECT没有 FROM条款。尝试添加 FROM DUAL ，因为这个最外层 SELECT不从任何表中选择。

PL/SQL 赋值运算符是 := ，不是 = .分配给 :NEW.AMOUNT ，你需要写:NEW.AMOUNT := (:NEW.AMOUNT * 0.1); .

将金额乘以 0.1 会给客户 90% 的折扣，而不是 10% 的折扣。