Question

您好我正在制作一个SQL触发器，应该说“在 CUSTOMER_ALIAS 表中插入行时，检查该行中的三个地址列中是否包含任何一行 US_STATES 表格中存在的值（由一列 - “ COUNTRY_NAME ”组成），如果客户的地址是美国州，则设置当前正在插入'true'

的那一行的INDICIA_STATE

CREATE TRIGGER ADDRESS_T BEFORE INSERT ON MYDB.CUSTOMER_ALIAS 
    REFERENCING NEW ROW AS NEW_ROW
        WHEN
            EXISTS(SELECT * FROM MYDB.US_STATES WHERE US_STATES.COUNTRY_NAME = NEW_ROW.ADDRESS_1_COUNTRY OR US_STATES.COUNTRY_NAME = NEW_ROW.ADDRESS_2_COUNTRY OR US_STATES.COUNTRY_NAME = NEW_ROW.ADDRESS_3_COUNTRY)
        THEN SET NEW_ROW.INDICIA_STATE= 'true'
;

我收到此错误

Error: DB2 SQL Error: SQLCODE=-104, SQLSTATE=42601, SQLERRMC=CREATE TRIGGER ADDRESS_T BEFORE INSERT ON D;BEGIN-OF-STATEMENT;<space>, DRIVER=4.16.53
SQLState:  42601
ErrorCode: -104

根据IBM's error code list似乎是一个语法错误，但我不明白它来自哪里。这个触发器看起来怎么样？

Answer 1

我认为then不是触发器语法的一部分。您还可以使用in简化逻辑。所以这可能有用：

CREATE TRIGGER ADDRESS_T BEFORE INSERT ON MYDB.CUSTOMER_ALIAS 
    REFERENCING NEW ROW AS NEW_ROW
    FOR EACH ROW
    WHEN EXISTS(SELECT 1 FROM MYDB.US_STATES WHERE US_STATES.COUNTRY_NAME IN (NEW_ROW.ADDRESS_1_COUNTRY, NEW_ROW.ADDRESS_2_COUNTRY, NEW_ROW.ADDRESS_3_COUNTRY)
               )
        SET NEW_ROW.INDICIA_STATE = 'true';

Answer 2

除了戈登所说的你应该说明它是行还是声明触发器之外，我还认为WHEN子句需要它自己的一组括号：

CREATE TRIGGER ADDRESS_T 
BEFORE INSERT ON MYDB.CUSTOMER_ALIAS
REFERENCING NEW ROW AS NEW_ROW 
FOR EACH ROW
WHEN (
  EXISTS (
    SELECT * FROM MYDB.US_STATES 
    WHERE US_STATES.COUNTRY_NAME = NEW_ROW.ADDRESS_1_COUNTRY 
        OR US_STATES.COUNTRY_NAME = NEW_ROW.ADDRESS_2_COUNTRY 
        OR US_STATES.COUNTRY_NAME = NEW_ROW.ADDRESS_3_COUNTRY
  )
)
    SET NEW_ROW.INDICIA_STATE= 'true'

使用不同的表触发检查条件，然后根据结果更改要插入的行的值

2 个答案: