單行MERGE/upsert SQL Server中的語法

Question

我正在嘗試在表上執行單行插入/更新操作，但所有示例均爲集合。

任何人都可以解決我的語法請：每marc_s

MERGE member_topic ON mt_member = 0 AND mt_topic = 110 
WHEN MATCHED THEN UPDATE SET mt_notes = 'test' 
WHEN NOT MATCHED THEN INSERT (mt_member, mt_topic, mt_notes) VALUES (0, 110, 'test') 

分辨率是單列轉換爲子查詢 - 這讓我想起了MERGE命令是不是真的打算單列upserts。

MERGE member_topic 
USING (SELECT 0 mt_member, 110 mt_topic) as source 
ON member_topic.mt_member = source.mt_member AND member_topic.mt_topic = source.mt_topic 
WHEN MATCHED THEN UPDATE SET mt_notes = 'test' 
WHEN NOT MATCHED THEN INSERT (mt_member, mt_topic, mt_notes) VALUES (0, 110, 'test'); 

Answer 1

基本上，你在正確的軌道上 - 但你缺少從您要合併的數據源 - 嘗試這樣的事：

MERGE 
    member_topic AS target 
USING 
    someOtherTable AS source 
ON 
    target.mt_member = source.mt_member 
    AND source.mt_member = 0 
    AND source.mt_topic = 110 
WHEN MATCHED THEN 
    UPDATE SET mt_notes = 'test' 
WHEN NOT MATCHED THEN 
    INSERT (mt_member, mt_topic, mt_notes) VALUES (0, 110, 'test') 
; 

沒有特殊的語法對於單行MERGE - 您需要做的就是使用適當的子句。通過ON條款中的適當條件，您可以將源限制爲單行 - 沒有問題。

而且不要忘記尾隨分號！沒有開玩笑 - 這很重要！

看到this blog post爲MERGE一個很好的介紹。

Answer 2

我終於得到了使用SQL Server 2008中MERGE的語法的Upsert使用什麼雅各布想做的（一個的Upsert）：

IF EXISTS(SELECT * FROM member_topic WHERE mt_member = 0 AND mt_topic = 110) 
BEGIN 
    --update existing row 
    UPDATE member_topic SET mt_notes = 'test' 
    WHERE mt_member = 0 
    AND mt_topic = 110 
END 
ELSE 
BEGIN 
    --insert new row 
    INSERT INTO member_topic (mt_member, mt_topic, mt_notes) 
    VALUES (0, 110, 'test') 
END 

等效MERGE語法是：

MERGE member_topic 
USING ( 
    VALUES (0, 110, 'test') 
) AS foo (mt_member, mt_topic, mt_notes) 
ON member_topic.mt_member = foo.mt_member 
    AND member_topic.mt_topic = foo.mt_topic 
WHEN MATCHED THEN 
    UPDATE SET mt_notes = foo.mt_notes 
WHEN NOT MATCHED THEN 
    INSERT (mt_member, mt_topic, mt_notes) 
    VALUES (foo.mt_member, foo.mt_topic, foo.mt_notes) 
; --A MERGE statement must be terminated by a semi-colon (;).