Scope_IDENTITYでMERGE INTOを使用する

Question

Merge intoがinsertの場合、Scope_Identityは正しい代理キー情報を返します。しかしupdateがScope_Identityと@@Identity両方が次可能な代理キーを返す行われた場合。私はoutputを追加したとき、私はupdateとinsertの両方にヌルを取得します。

updateとinsertの両方で代理キーを返すにはどうすればよいですか？

DECLARE @Surrogate_KEY bigint 


MERGE INTO [dbo].[MyTable] ChangeSet 
USING (SELECT @NaturalKey1 AS NaturalKey1, 
       @NaturalKey2 AS NaturalKey2, 
       @NaturalKey3 AS NaturalKey3, 
       @Surrogate_KEY AS Surrogate_KEY) CurrentSet 
ON ChangeSet.NaturalKey1 = CurrentSet.NaturalKey1 AND 
    ChangeSet.NaturalKey2 = CurrentSet.NaturalKey2 AND 
    ChangeSet.NaturalKey3 = CurrentSet.NaturalKey3  
WHEN MATCHED THEN 
    UPDATE SET blah, blah, blah 

WHEN NOT MATCHED 
    THEN INSERT VALUES 
     (
     blah, blah, blah 
     ) 

output CurrentSet.*, @Surrogate_KEY ; 

print @Surrogate_KEY 
print @@IDENTITY 
print SCOPE_IDENTITY() 

Answer 1

あなたOUTPUT clauseにinserted擬似テーブルを使用します。

DECLARE @Surrogate_KEY bigint 


MERGE INTO [dbo].[MyTable] ChangeSet 
USING (SELECT @NaturalKey1 AS NaturalKey1, 
       @NaturalKey2 AS NaturalKey2, 
       @NaturalKey3 AS NaturalKey3, 
       @Surrogate_KEY AS Surrogate_KEY) CurrentSet 
ON ChangeSet.NaturalKey1 = CurrentSet.NaturalKey1 AND 
    ChangeSet.NaturalKey2 = CurrentSet.NaturalKey2 AND 
    ChangeSet.NaturalKey3 = CurrentSet.NaturalKey3  
WHEN MATCHED THEN 
    UPDATE SET blah, blah, blah 

WHEN NOT MATCHED 
    THEN INSERT VALUES 
     (
     blah, blah, blah 
     ) 

output inserted.* ; 

これは、値が文の終わりに（影響を受けた行の）テーブルにあるものを返します。

Answer 2

DECLARE @Id ... 
-- 
MERGE 
    dbo.Table AS Tgt 
USING 
    (
     SELECT 
      <Keys> 
    ) AS Src 
    ON Src.<Keys> = Tgt.<Keys> 
WHEN MATCHED THEN 
    UPDATE SET 
     <...> 
     ,@Id = Tgt.Id 
WHEN NOT MATCHED THEN 
    INSERT 
    (
     ... 
    ) 
    VALUES 
    (
     ... 
    ) 
;-- 
RETURN/SET/PRINT ISNULL(@Id, SCOPE_IDENTITY())