在MERGE命令中返回插入的更新记录的ID

Question

我需要在项目中插入/更新项目并返回记录的ID。这是我的T-SQL：

BEGIN
   MERGE [AgentDumps] WITH (HOLDLOCK) AS Target
   USING (SELECT @AgentID) AS Source (AgentID)
   ON (target.AgentID = source.AgentID)
   WHEN MATCHED THEN
     UPDATE
       Set DumpData = @DumpData,
           UpdateTime = getdate()
   WHEN NOT MATCHED THEN
     INSERT 
       ([AgentID],
        [DumpData]
       )
     VALUES 
       (
         @AgentID,
         @DumpData
       );
    SELECT CAST(scope_identity() AS int)
  END

仅在插入新记录时才有效。但是如果更新现有的查询，则返回null。我尝试在Update命令中添加OUTPUT INSERTED.ID：

BEGIN
   MERGE [AgentDumps] WITH (HOLDLOCK) AS Target
   USING (SELECT @AgentID) AS Source (AgentID)
   ON (target.AgentID = source.AgentID)
   WHEN MATCHED THEN
     UPDATE
       Set DumpData = @DumpData,
           UpdateTime = getdate()
           OUTPUT INSERTED.ID
   WHEN NOT MATCHED THEN
     INSERT 
       ([AgentID],
        [DumpData]
       )
     VALUES 
       (
         @AgentID,
         @DumpData
       );
    SELECT CAST(scope_identity() AS int)
  END

但SQL返回：关键字'WHEN'附近的语法不正确。