Merge insert with select statement

问题

This works for me

MERGE Table1 AS tgt
USING
(
    SELECT
        TOP 1
        *
    FROM
        Table2,
        (
            SELECT
                itmid
            FROM
                Table3
            WHERE
                id = @id
        ) as a
    WHERE
        id = @id
) AS src
ON ( tgt.id = src.id )
WHEN MATCHED THEN
    UPDATE SET qty = qty + @qty
WHEN NOT MATCHED THEN
    INSERT itmid
    VALUES itmid;

But when i change like this, its not working, showing error near last select

MERGE Table1 AS tgt
USING
(
    SELECT
        TOP 1
        *
    FROM
        Table2
    WHERE
        id = @id
) AS src
ON ( tgt.id = src.id )
WHEN MATCHED THEN
    UPDATE SET qty = qty + @qty
WHEN NOT MATCHED THEN
    INSERT itmid
    SELECT itmid FROM Table3 WHERE id = @id;

回答1:

According to MSDN docs

<merge_not_matched>::=
{
    INSERT [ ( column_list ) ] 
        { VALUES ( values_list )
        | DEFAULT VALUES }
}

The syntax with INSERT from SELECT like:

  WHEN NOT MATCHED THEN
            INSERT itmid SELECT itmid FROM Table3 WHERE id=@id;

Is not allowed!

I would try to solve your problem doing another merge with Table3.

回答2:

do this

 MERGE Table1 AS tgt
 USING (SELECT TOP 1 * FROM Table2
        WHERE id = @id) AS src
ON (tgt.id = src.id)
            WHEN MATCHED THEN UPDATE SET qty = qty + @qty
            WHEN NOT MATCHED THEN
                INSERT (itmid) 
                 SELECT itmid FROM Table3 WHERE id=@id;

Should work fine according to http://msdn.microsoft.com/en-us/library/bb522522(v=sql.105).aspx

Sorry I interpreted it wrong and my original answer would stand which was

MERGE Table1 AS tgt
     USING (SELECT TOP 1 * FROM Table2
            WHERE id = @id) AS src
    ON (tgt.id = src.id)
                WHEN MATCHED THEN UPDATE SET qty = qty + @qty
                WHEN NOT MATCHED THEN
                    INSERT (itmid) values (SELECT top 1 itmid FROM Table3 WHERE id=@id);

As merge insert takes one insert at a time and it might fail for multiple inserts.

来源：https://stackoverflow.com/questions/14646585/merge-insert-with-select-statement

标签

sql

sql-server

merge

sql-server-2008-r2