如何使用合并更新语句？ [英] How do I use the merge update statement?

问题描述

我已经将sql语句转换为我认为在vb.net中可用的字符串格式。



这是字符串出来的

使用[table2]将[table1]合并为T，在t.first_name = S.first_name上为S，匹配时为T.age = s.age，然后更新Set T.last_name = S.Last_name; 

当我去检查表1中没有任何变化的数据时，如果我遗漏了某些内容或者某些内容，有人可以根据字符串告诉我错误的地方？



我的尝试：



没有数据正被插入到姓氏列中，它保持空白。我已从列名中删除了括号并添加了逗号，但无济于事，我在更新的last_name列中仍然没有得到任何内容。

解决方案

查询看起来很好，检查表中的条件是否匹配，您可以使用联接来查找

 SELECT * FROM Table_1，Table_2 
 WHERE Table_1.first_name = Table_2.first_name和Table_1.age = Table_2.age 

 MERGE [Table1] T 
使用[table2] S 
 ON t.first_name = S.first_name和T.age = s.age 
 WHEN MATCHED THEN UPDATE SET T.last_name = S.Last_name 

I have turned the sql statement into what I thought was a usable string format in vb.net.

Here is what the string comes out to be

Merge into [Table1] as T using [table2] as S on t.first_name = S.first_name and T.age = s.age when matched then update Set T.last_name = S.Last_name;

when I go to check the data nothing changes in table 1, could someone tell me based upon the string if I am missing something or if something is in the wrong place?

What I have tried:

No data is being inserted into the last name column it is staying blank. I have removed the brackets from the column names and added commas, but to no avail, I am still getting nothing in the last_name column updated.

解决方案

Query looks fine, Check whether the condition matches in both the table, you can use a join for finding out that

SELECT * FROM Table_1, Table_2 
WHERE Table_1.first_name = Table_2.first_name and  Table_1.age = Table_2.age

MERGE [Table1] T 
USING  [table2] S
ON t.first_name = S.first_name and T.age = s.age
WHEN MATCHED THEN UPDATE SET T.last_name = S.Last_name

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