MSSQL 插入數據時候，如果存在則更新的方法分享

摘要:
下文講述MSSQL中，插入數據時，如果存在則更新,否則就插入數據的方法分享
實驗環境:sql server 2017 
mssql中，我們可以采用 MERGE INTO 關鍵字實現此功能，
當兩者匹配成功，則運行***語句，否則運行其它語句，達到插入數據時的判斷操作，
具體操作方法如下所示: 

create table [maomao365.com]
(keyId int identity,
info varchar(80)
)
go
insert into [maomao365.com]
(info)values('sqlblog'),
('sqlserver'),('maomao365.com')

---merge into實現如果存在，則更新
---如果不存在，則刪除
MERGE INTO [maomao365.com] a
USING (SELECT 2 AS keyId_B, 'other' AS info_B ) b 
ON ( a.keyId = b.keyId_B)

WHEN MATCHED THEN
UPDATE SET a.info= b.info_B --更新

WHEN NOT MATCHED THEN
INSERT (info) VALUES(b.info_B); ---插入

go
select * from [maomao365.com]
go
MERGE INTO [maomao365.com] a
USING (SELECT 20 AS keyId_B, 'new Info' AS info_B ) b 
ON ( a.keyId = b.keyId_B)

WHEN MATCHED THEN
UPDATE SET a.info= b.info_B --更新

WHEN NOT MATCHED THEN
INSERT (info) VALUES(b.info_B); ---插入
go

select * from [maomao365.com]
go
truncate table [maomao365.com]
drop table [maomao365.com]

轉自：

 http://www.maomao365.com/?p=9679

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