使用MERGE同步2個表格

Question

我的任務是同步2個表格（兩者完全相同）。他們每個有60列。表A是最初將填寫的主表。我需要創建一個存儲過程（完成），它將合併這兩個表，並在調用時填充相同的確切數據（更新，插入，刪除）。我如何使用SQL中的MERGE函數來實現這一點？我已經查看了MSDN文檔以及technet上的類似文檔，但是我對入門感到困惑。我是否需要指定我需要合併的每個字段？或者這是一個簡單的電話，我錯過了將執行此操作？

Answer 1

這裏是MERGE語句的一個簡單的例子鏈接：

http://www.simple-talk.com/sql/learn-sql-server/the-merge-statement-in-sql-server-2008/

的基本語法讀作：

MERGE table1 
USING table2 
ON table1.id = table2.id 
WHEN MATCHED THEN 
--Do an update here 
WHEN NOT MATCHED BY TARGET THEN 
--Do an insert here (or a delete) 
; 

您還可以使用WHEN NOT MATCHED BY SOURCE

Answer 2

超過60列是一個偉大的數字！當我需要同步2個相同的表我做：

;WITH tbl_to_synch as (
    -- Prepare table to update, 
    Select *,chk = CHECKSUM(*) from [dbo].[tableA] 
) 
MERGE tbl_to_synch as [Target] 
USING (Select *,chk = CHECKSUM(*) from [dbo].[tableB]) as [source] 
ON [Target].key = [source].key 
WHEN MATCHED AND [Target].chk <> [source].chk THEN 
-- UPDATE ONLY row that is changed 
UPDATE 
    SET 
     column01 = [source].[column01] 
     ,column02 = [source].[column01] 
     -- .... 
     ,column59 = [source].[column59] 
     ,column60 = [source].[column59] 

WHEN NOT MATCHED BY TARGET THEN 
    insert (column01, column02, ...,column59,column60) 
    values (column01, column02, ...,column59,column60) 
WHEN NOT MATCHED BY SOURCE THEN DELETE 
-- Show what is changed 
OUTPUT $action, ISNULL(INSERTED.key,DELETED.key);