Sql 使用聚合函数SUM更新

以下SQL语句工作正常：

SELECT  SUM(IIF(srsFromStock, srsAmount, 0)), srvID
FROM tblServices AS S INNER JOIN tblServicesSub AS SS ON S.srvID =
SS.srssrvID 
GROUP BY srvID

我想将此选择转换为更新，但尚未成功：

UPDATE tblServices AS S INNER JOIN tblServicesSub AS SS ON S.srvID =
SS.srssrvID  SET srvSumFromStock = SUM(IIF(srsFromStock, srsAmount,
0)) GROUP BY srvID

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发生了什么以及如何修复它？

不能使用聚合值进行更新。若在这种情况下，我将使用表变量或临时表来保存聚合结果，然后连接表并更新它们。像这样的事情：

   DECLARE @tempTbl TABLE (srssrvID INT,aggregate_sum DECIMAL(18,4))
   INSERT INTO @tempTbl SELECT srssrvID,SUM(IIF(srsFromStock, srsAmount, 0)) FROM tblServicesSub GROUP BY srssrvID
   UPDATE tblServices INNER JOIN @tempTbl ON srssrvID=srvID
   SET srvSumFromStock=aggregate_sum

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无法使用聚合值进行更新。若在这种情况下，我将使用表变量或临时表来保存聚合结果，然后连接表并更新它们。像这样的事情：

   DECLARE @tempTbl TABLE (srssrvID INT,aggregate_sum DECIMAL(18,4))
   INSERT INTO @tempTbl SELECT srssrvID,SUM(IIF(srsFromStock, srsAmount, 0)) FROM tblServicesSub GROUP BY srssrvID
   UPDATE tblServices INNER JOIN @tempTbl ON srssrvID=srvID
   SET srvSumFromStock=aggregate_sum