Question

我有这个触发器

ALTER TRIGGER [dbo].[tInsertTaskFromOpportunityReassignment] 
   ON [dbo].[OpportunityBase]
   FOR UPDATE
AS 
BEGIN

IF UPDATE(owninguser)
BEGIN
-- do the task
END
END

如果owninguser实际发生了变化，我只想完成任务。我该如何确定？

由于

Answer 1

ALTER TRIGGER [dbo].[tInsertTaskFromOpportunityReassignment] 
   ON [dbo].[OpportunityBase]
   FOR UPDATE
AS 
BEGIN
DECLARE HasChanged int = 0;

SELECT @HasChanged = 1
FROM Inserted AS I
INNER JOIN Deleted AS D
ON I.PK = D.PK
AND IsNull(I.owninguser,'~') <> IsNull(D.owninguser,'~')

IF @HasChanged = 1
BEGIN
-- do the task
END
END

比较Inserted和Deleted之间的字段值，并连接主键上的两个表。

Answer 2

ALTER TRIGGER [dbo].[tInsertTaskFromOpportunityReassignment] 
   ON [dbo].[OpportunityBase]
   FOR UPDATE
AS
BEGIN
/*
    I will assume that your [dbo].[OpportunityBase] table has a PRIMARY KEY
    or UNIQUE column that is immutable to join the inserted and deleted
    tables. In this example, [OpportunityBaseId] is that column.

    The SELECT query returns a set of all records that had the value of [owninguser] 
    changed. What you would do from that point is up to you.
*/
SELECT 
    i.[OpportunityBaseId], i.owninguser New_owninguser, d.owninguser Old_owninguser
FROM inserted i
JOIN deleted d
    ON i.[OpportunityBaseId] = d.[OpportunityBaseId]
    AND 
        (
            --owninguser value was changed.
            i.[owninguser] <> d.[owninguser] OR 

            --owninguser changed from non-NULL to NULL.
            (i.[owninguser] IS NULL AND d.[owninguser] IS NOT NULL) OR 

            --owninguser changed from NULL to non-NULL.
            (i.[owninguser] IS NOT NULL AND d.[owninguser] IS NULL)
        )
END 
GO

Answer 3

我喜欢使用concat，尽管它可能会导致您出现NULL和''的问题：

CONCAT('', inserted.owninguser) <> CONCAT('', deleted.owninguser)

SQL触发器 - 确定字段是否已更改

3 个答案: