避免在 SQL SERVER 中重复插入的条件

Question

我需要做什么

1. 如果存在重复行，请不要插入。
2. 如果存在相同的party_num 但其他列的值不同，请更新该party num 的其他列的现有值。

由于源表和目标表有超过 50 万条记录，最好的方法是什么？

 INSERT INTO STAGING_CUST_ACCT

        SELECT 
            [CUSTOMER KEY]      AS [PARTY_NUM]
            ,[ACCOUNT CITY]             AS [PRIMARY CITY]
            ,[ACCOUNT STATE]            AS [PRIMARY STATE]
            ,[ACCOUNT ZIP]              AS [PRIMARY ZIP]
        FROM [RCC_CLOSED]  

Answer 1

;
WITH changed_rows_only AS (
    SELECT [CUSTOMER KEY],[ACCOUNT CITY],[ACCOUNT STATE],[ACCOUNT ZIP] FROM RCC_CLOSED
    EXCEPT
    SELECT [PARTY_NUM]   ,[PRIMARY CITY],[PRIMARY STATE],[PRIMARY ZIP] FROM STAGING_CUST_ACCT
)
MERGE INTO STAGING_CUST_ACCT AS tgt
USING changed_rows_only AS src
ON (
  src.[CUSTOMER KEY] = tgt.[CUSTOMER KEY]
)
WHEN MATCHED THEN UPDATE SET
  tgt.[PRIMARY CITY]  = src.[ACCOUNT STATE]
 ,tgt.[PRIMARY STATE] = src.[ACCOUNT STATE]
 ,tgt.[PRIMARY ZIP]   = src.[ACCOUNT ZIP]
WHEN NOT MATCHED THEN
  INSERT(    [PARTY_NUM]   ,    [PRIMARY CITY],    [PRIMARY STATE],    [PRIMARY ZIP])
  VALUES(src.[CUSTOMER KEY],src.[ACCOUNT CITY],src.[ACCOUNT STATE],src.[ACCOUNT ZIP]);