合并时不匹配来源和

Question

我有一个表'groups',里面有一些数据:

groupid     groupname       grouptext
1           Cars            Toyota
2           Cars            BMW
3           Cars            Renault
4           Bikes           BMW
5           Bikes           Yamaha

之后,我是以下SQL语句,其中我尝试使用MERGE语句更新groups表.我想要做的是使用XML中的数据更新groups表.但我还想删除表中其组名存在于XML中的所有条目.因此,例如在执行后,我的表应该如下所示

groupid     groupname       grouptext
1           Cars            Audi
4           Bikes           BMW
5           Bikes           Yamaha
6           Singers         Lady Gaga

因为,有组名,汽车在那里,所有的汽车应该从表中删除.现在,当我使用WHEN NOT MATCHED BY SOURCE AND子句时,我收到此错误:

Msg 5334, Level 16, State 2, Line 60
The identifier 's.groupname' cannot be bound. Only target columns and columns in the clause scope are allowed in the 'WHEN NOT MATCHED BY SOURCE' clause of a MERGE statement.
Msg 5334, Level 16, State 2, Line 61
The identifier 's.grouptext' cannot be bound. Only target columns and columns in the clause scope are allowed in the 'WHEN NOT MATCHED BY SOURCE' clause of a MERGE statement.

我的问题是,如何使用以下代码实现所需的结果:

DECLARE @UpdateXml Xml = N'<groups>
    <group>
        <groupid>1</groupid>
        <groupname>Cars</groupname>
        <grouptext>Audi</grouptext>
    </group>
    <group>
        <groupid>0</groupid>
        <groupname>Singers</groupname>
        <grouptext>Lady Gaga</grouptext>
    </group>
</groups>';

DECLARE @hDoc INT;
EXEC sp_xml_preparedocument @hDoc OUTPUT, @UpdateXml;

MERGE INTO groups AS t
USING
(
    SELECT groupid, groupname, grouptext
    FROM OPENXML(@hdoc, '/groups/group', 1)
    WITH
    (
        groupid INT 'groupid',
        groupname VARCHAR(50) 'groupname',
        grouptext VARCHAR(100) 'grouptext'
    )
) AS source(groupid, groupname, grouptext)

ON
    t.groupid = source.groupid AND
    t.groupname = source.groupname

WHEN MATCHED THEN
UPDATE SET
    groupname = source.groupname,
    grouptext = source.grouptext

WHEN NOT MATCHED BY TARGET THEN
    INSERT (groupname, grouptext)
    VALUES (source.groupname, source.grouptext)

WHEN NOT MATCHED BY SOURCE AND
    s.groupname = t.groupname AND
    s.grouptext = t.grouptext
        THEN
            delete
;

Answer 1

当MERGE语句中没有匹配的SOURCE子句时,只有TARGET表中的列除外.您可以使用SubQuery,例如:

WHEN NOT MATCHED BY SOURCE AND
    t.groupname IN (SELECT s.groupname FROM table_name where xyz_condition)