SQL Server MERGE 2 Table อยากให้เช็ค LastEditDate ว่าแถวไหนวันเวลาล่ามากสุดเอาเป็นตัวตั้ง แล้ว Update ใส่แถวตัวที่มีวันเวลาน้อย

MERGE INTO [dbo].[ITEMS] AS TARGET 
  USING [PRODUCT].[NARO].[dbo].[ITEMS] AS SOURCE
  ON (TARGET .Code=SOURCE.Code)
WHEN NOT MATCHED BY TARGET THEN
  INSERT (Code, Name, Unit, CreateDateTime, LastEditDateT, Status)
  VALUES (SOURCE.Code, SOURCE.Name, SOURCE.Unit, SOURCE.CreateDateTime, SOURCE.LastEditDateT, SOURCE.Status)
WHEN MATCHED AND b.LastEditDateT > a.LastEditDateT THEN
  UPDATE SET a.Code=b.Code, 
a.Name=b.Name, 
a.Unit=b.Unit, 
a.CreateDateTime=b.CreateDateTime, 
a.LastEditDateT=b.LastEditDateT, 
a.Status=b.Status
WHEN NOT MATCHED BY SOURCE
  THEN DELETE;

MERGE INTO [PRODUCT].[NARO].[dbo].[ITEMS] AS TARGET 
  USING [dbo].[ITEMS] AS SOURCE
  ON (TARGET .Code=SOURCE.Code)
WHEN NOT MATCHED BY TARGET THEN
  INSERT (Code, Name, Unit, CreateDateTime, LastEditDateT, Status)
  VALUES (SOURCE.Code, SOURCE.Name, SOURCE.Unit, SOURCE.CreateDateTime, SOURCE.LastEditDateT, SOURCE.Status)
WHEN MATCHED AND b.LastEditDateT > a.LastEditDateT THEN
  UPDATE SET a.Code=b.Code, 
a.Name=b.Name, 
a.Unit=b.Unit, 
a.CreateDateTime=b.CreateDateTime, 
a.LastEditDateT=b.LastEditDateT, 
a.Status=b.Status
WHEN NOT MATCHED BY SOURCE
  THEN DELETE;