Question

我想创建一个Insert触发器，如果它们为null，则更新所有插入行的值，新值应根据插入表中的另一列从不同的表中获取。

我试过了：

UPDATE INSERTED
SET TheColumnToBeUpdated = 
    (
    SELECT TheValueCol FROM AnotherTable.ValueCol
    WHERE AnotherTable.ValudCol1 = INSERTED.ValueCol1
    )
WHERE ValueCol IS NULL

但是我收到了这个错误：

Msg 286, Level 16, State 1, Procedure ThisTable_INSERT, Line 15
The logical tables INSERTED and DELETED cannot be updated.

我该怎么做？

Answer 1

您需要更新目标表，而不是逻辑表。但是，您可以使用逻辑表连接以确定要更新的行：

UPDATE YourTable
SET TheColumnToBeUpdated = 
    (
    SELECT TheValueCol FROM AnotherTable.ValueCol
    WHERE AnotherTable.ValudCol1 = INSERTED.ValueCol1
    )
FROM YourTable Y
JOIN Inserted I ON Y.Key = I.Key
WHERE I.ValueCol IS NULL

Answer 2

您可以将触发器更改为INSTEAD OF INSERT。这将允许您检查传入的值，如果需要，可以使用其他表中的值替换它们。

CREATE TRIGGER CoolTrigger 
ON MyAwesomeTable 
INSTEAD OF INSERT
AS 
BEGIN  

INSERT MyAwesomeTable (TheValueCol)
SELECT ISNULL(INSERTED.TheValueCol, AnotherTable.TheValueCol) AS TheValueCol
FROM INSERTED
JOIN AnotherTable ON INSERTED.ValueCol1 = AnotherTable.ValueCol1

END

注意：INSTEAD OF触发器不会导致递归。

Answer 3

insert into output  
(SELECT t1.ts - INTERVAL (SECOND(t1.ts)%10) SECOND,  
t1.ts - INTERVAL (SECOND(t1.ts)%10) SECOND + INTERVAL 10 SECOND ,sum(t1.data),   
FROM (select * from input   
where unix_timestamp(ts) >= unix_timestamp('2000-01-01 00:00:10')  
and unix_timestamp(ts) < unix_timestamp('2000-01-01 00:01:20')  
)
  as t1   
GROUP BY UNIX_TIMESTAMP(t1.ts) DIV 10 );

这是我的输出表的来源。因此插入不是值。

我很抱歉，但我无法从这里（办公室）访问我的帐户，

SQL插入触发器以更新INSERTED表值

3 个答案: