sql - SQL MERGE ステートメントで GROUP BY 句を使用するにはどうすればよいですか?

Question

2 つのテーブルをマージしようとしていますが、次のエラーを修正するために GROUP BY を使用したいと考えています。

The MERGE statement attempted to UPDATE or DELETE the same row more than once. This happens when a target row matches more than one source row. A MERGE statement cannot UPDATE/DELETE the same row of the target table multiple times. Refine the ON clause to ensure a target row matches at most one source row, or use the GROUP BY clause to group the source rows.

GROUP BY 句は正確にはどこに行くのでしょうか?

MERGE dbo.MyTarget targ
USING dbo.MySource src
ON (targ.Identifier = src.Identifier
    AND targ.Name = src.ConstituentName
    AND targ.Ticker = src.ConstituentTicker
    AND (targ.CUSIP = src.CUSIP OR targ.ISIN = src.ISIN OR targ.SEDOL = src.SEDOL))
WHEN MATCHED THEN
-- update values
;

Answer 1

このようなもの：

MERGE dbo.MyTarget targ
USING (SELECT ... FROM dbo.MySource GROUP BY .....) src
ON (targ.Identifier = src.Identifier
    AND targ.Name = src.ConstituentName
    AND targ.Ticker = src.ConstituentTicker
    AND (targ.CUSIP = src.CUSIP OR targ.ISIN = src.ISIN OR targ.SEDOL = src.SEDOL))
WHEN MATCHED THEN
-- update values
;