sql - 使用聚合自联接更新查询

Question

我正在使用自加入来获取年初至今的总数。这有效：

SELECT tc.EmployeeID, tc.TimeCardNum, tc.Tax, SUM(inr.Tax) AS YTDTax
FROM TimeCards tc
JOIN (
        SELECT EmployeeID, TimeCardNum, Tax
        FROM TimeCards  
) AS inr
ON inr.EmployeeID = tc.EmployeeID
AND inr.TimeCardNum <= tc.TimeCardNum
GROUP BY tc.EmployeeID, tc.TimeCardNum, tc.Tax
ORDER BY tc.EmployeeID, tc.TimeCardNum

这给了我一个为每个员工重置的运行总计列。

现在我想把它变成一个UPDATE查询，将该数据放入一个新列中。这是怎么做到的？

Answer 1

你有没有尝试过：

UPDATE a
SET a.YTDTax=b.YTDTax
FROM TimeCards a
INNER JOIN (
    SELECT tc.EmployeeID, tc.TimeCardNum, tc.Tax, SUM(inr.Tax) AS YTDTax
    FROM TimeCards tc
    JOIN (
            SELECT EmployeeID, TimeCardNum, Tax
            FROM TimeCards  
    ) AS inr
    ON inr.EmployeeID = tc.EmployeeID
    AND inr.TimeCardNum <= tc.TimeCardNum
    GROUP BY tc.EmployeeID, tc.TimeCardNum, tc.Tax
) b on a.EmployeeID=b.EmployeeID
AND a.TimeCardNum = b.TimeCardNum

在事务中运行以确保它产生所需的输出。