Oracle：WITH AS () Merge ?

WITH expression_name [ ( column_name [,...n] ) ]
AS
( CTE_query_definition )
--只有在查询定义中为所有结果列都提供了不同的名称时，列名称列表才是可选的。
--运行 CTE 的语句为：
SELECT <column_list> FROM expression_name;

MERGE INTO #TEMP1 A
USING (
WITH SUMORDER AS 
       (SELECT PRODUCTID, SUM(AMOUNT) TOTAL 
        FROM ORDER GROUP BY PRODUCTID)
       SELECT * FROM SUMORDER
) B ON (A.PRODUCTID = B.PRODUCTID)
WHEN MATCHED THEN UPDATE SET A.TOTAL = B.TOTAL;