更新表從自身

Question

我試圖更新的滾動平均值計算一個臨時表（MS Access 2010中）

作爲一個選擇查詢，這個工程來計算3個月的移動平均值，但慢，所以我寧願存儲，只有在必要時更新的值：

SELECT tempQORDistGrouped.Type, tempQORDistGrouped.Supplier, tempQORDistGrouped.DepBkMo, tempQORDistGrouped.Amt, tempQORDistGrouped.Brands, tempQORDistGrouped.T2, tempQORDistGrouped.Brand, (select avg(rolavg.Amt) from tempQORDistGrouped as rolavg 
    where rolavg.Type = tempQORDistGrouped.Type 
    and rolavg.Supplier = tempQORDistGrouped.Supplier 
    and rolavg.Brands = tempQORDistGrouped.Brands 
    and rolavg.Brand = tempQORDistGrouped.Brand 
    and rolavg.DepBkMo between dateadd("m",-2,tempQORDistGrouped.DepBkMo) and tempQORDistGrouped.depbkmo) AS AvgAmt 
FROM tempQORDistGrouped; 

我試過下面的更新查詢，但我覺得我的內部聯接語法糟糕，因爲它不會承認x1.Type爲一個有效的字段（我是否需要將這些字段作爲內部連接字段的一部分而不是在where子句中？）：

個

UPDATE tempQORDistGrouped AS x1 
INNER JOIN (SELECT itmID, avg(Amt) AS RolAvg 
    FROM tempQORDistGrouped 
    WHERE tempQORDistGrouped.Type = x1.Type 
    AND tempQORDistGrouped.Brand = x1.Brand 
    AND tempQORDistGrouped.Brands = x1.Brands 
    AND tempQORDistGrouped.T2 = x1.T2 
    AND tempQORDistGrouped.DepBkMo between dateadd("m",-2,x1.DepBkMo) and x1.DepBkMo 
    GROUP BY itmID 
) AS x2 
ON x1.itmID = x2.itmID 
SET x1.3MonthRollingAmt = x2.RolAvg; 

乾杯

Answer 1

未經測試，但應該工作。 我做了列級查詢計算AVG，然後映射回列的其餘

試試這個：

UPDATE tempQORDistGrouped AS x1 
INNER JOIN (
    SELECT itmID 
     , (
      SELECT avg(Amt) amt 
      FROM tempQORDistGrouped x4 
      WHERE x4.Type = x3.Type 
       AND x4.Brand = x3.Brand 
       AND x4.Brands = x3.Brands 
       AND x4.T2 = x3.T2 
       AND x4.DepBkMo BETWEEN dateadd("m", - 2, x3.DepBkMo) AND x3.DepBkMo 
      ) AS RolAvg 
     , x3.Brand 
     , x3.Brands 
     , x3.DepBkMo 
     , x3.T2 
    FROM tempQORDistGrouped x3 
    ) AS x2 
    ON x1.itmID = x2.itmID 
     AND x1.Brand = x2.Brand 
     AND x1.Brands = x2.Brands 
     AND x1.T2 = x2.T2 
     AND x1.DepBkMo BETWEEN dateadd("m", - 2, x2.DepBkMo) AND x2.DepBkMo  
SET x1.3MonthRollingAmt = x2.RolAvg;