SQL Server 表连接删除

一哥们在做数据同步的时候写了个游标去循环更新数据库里面的表记录：

-- Following is incremental update 

DECLARE @InterfaceCode_tmp varchar(12), @Affiliate_tmp char(3),@DealerNumber_tmp varchar(5),@DSPNumber_tmp varchar(12) 

--Process DealerAuthorization 

DECLARE dealerAuth_cursor CURSORFOR

SELECT InterfaceCode,Affiliate,DealerNumber FROM DealerAuthorization_tmp

OPEN dealerAuth_cursor

FETCHNEXTFROM dealerAuth_cursor INTO @InterfaceCode_tmp,@Affiliate_tmp,@DealerNumber_tmp

WHILE@@FETCH_STATUS= 0

BEGIN 

DELETE DealerAuthorization WHERE InterfaceCode=@InterfaceCode_tmp and Affiliate=@Affiliate_tmp and DealerNumber=@DealerNumber_tmp 

INSERT INTO DealerAuthorization (InterfaceCode, Affiliate, DealerNumber, isValid,ExpireDate)

SELECT InterfaceCode, Affiliate, DealerNumber, isValid, ExpireDate

FROM DealerAuthorization_tmp WHERE InterfaceCode=@InterfaceCode_tmp and Affiliate=@Affiliate_tmp and DealerNumber=@DealerNumber_tmp

FETCH NEXTF ROM dealerAuth_cursor INTO @InterfaceCode_tmp,@Affiliate_tmp,@DealerNumber_tmp

END

CLOSE dealerAuth_cursor

DEALLOCATE dealerAuth_cursor

尼玛，我们数据库有5万多条数据，我不知道要执行多久。还好数据都不是很大，栏位也不多，他说只用一秒就完了。

想起以前写过一个，帮他改了下

DELETE　　FROM DealerAuthorization

FROM　　DealerAuthorization a inner join DealerAuthorization_tmp b

ON　　a.DealerNumber = b.DealerNumber and a.Affiliate = b.Affiliate and a.InterfaceCode = b.InterfaceCode

INSERT　　INTO　　DealerAuthorization(InterfaceCode, Affiliate, DealerNumber, isValid,ExpireDate)

SELECT　　InterfaceCode, Affiliate, DealerNumber, isValid,ExpireDate

FROM　　DealerAuthorization_tmp

看起来舒服多了。嘿嘿。