sql-server - 测试一个动作是否是触发器中的更新

Question

当执行删除/更新/插入操作时，我为表创建了触发器。

要测试它是否是删除，我使用以下语句：

if exists(select * from deleted)

如果它是一个插入：

if exists(select * from inserted)

但是我如何测试它是否是更新

Answer 1

 SET @action = 'I'; -- Set Action to Insert by default.
    IF EXISTS(SELECT * FROM DELETED)
    BEGIN
        SET @action = 
            CASE
                WHEN EXISTS(SELECT * FROM INSERTED) THEN 'U' -- Set Action to Updated.
                ELSE 'D' -- Set Action to Deleted.       
            END
    END
    ELSE 
    BEGIN
        IF NOT EXISTS(SELECT * FROM INSERTED) -- New record inserted.
             SET @action = 'I';
    END