将两列的值相加并显示在下一行

Posted 2023-03-31

【中文标题】将两列的值相加并显示在下一行

【英文标题】：Sum values of two columns and display in next row

【发布时间】：2020-12-04 07:38:35

【问题描述】：

我有一个如下所示的表格：

select * from #tempTable

    RN  Qty
    0   30
    1   -3
    2   -2
    3   8

使用下面的查询，我可以做到以下几点：

WITH CTE AS
(SELECT ROW_NUMBER()OVER(ORDER BY RN) AS RN, Qty
FROM #tempTable)

SELECT T1.RN,T1.Qty StartingQty,T2.Qty as ChangedQty, (T1.Qty+T2.Qty) as TotalQty
FROM CTE T1 LEFT JOIN
     CTE T2 ON T1.RN=(T2.RN-1) where T2.Qty IS not null

结果如下：

    RN  StartingQty ChangedQty  TotalQty
    1    30            -3         27
    2    -3            -2         -5
    3    -2             8          6

结果应该如下所示，不知道如何实现：

    RN  StartingQty ChangedQty  TotalQty
    1    30            -3         27
    2    27            -2         25
    3    25             8         33

任何线索都会对如何实现这一点有所帮助。

【问题讨论】：

SQL Server 版本是多少？

管理工作室 2018，版本 2016

正如我在 2016 年上面所说的。

【参考方案1】：

您可以尝试使用LEAD() 和窗口化SUM() 的方法：

SELECT *
FROM (
   SELECT
      RN,
      SUM(Qty) OVER (ORDER BY RN) AS StartingQty,
      LEAD(Qty) OVER (ORDER BY RN) AS ChangedQty,
      SUM(Qty) OVER (ORDER BY RN) + LEAD(Qty) OVER (ORDER BY RN) AS TotalQty
   FROM (VALUES
      (0, 30),
      (1, -3),
      (2, -2),
      (3, 8)
   ) v (RN, Qty)
) t
WHERE ChangedQty IS NOT NULL

结果：

RN  StartingQty ChangedQty  TotalQty
0            30         -3        27
1            27         -2        25
2            25          8        33

【参考方案2】：

您可以使用窗口函数和窗口框架获取基本值：

select rn, qty as StartingQty,
       lead(qty) over (order by rn) as ChangedQty,
       sum(qty) over (order by rn rows between unbounded preceding and 1 following) as TotalQty
from (values (0, 30),
             (1, -3),
             (2, -2),
             (3, 8)
     ) v (rn, Qty);

要消除最后一行，唉，你需要一个子查询：

select t.*
from (select rn, qty as StartingQty,
             lead(qty) over (order by rn) as ChangedQty,
             sum(qty) over (order by rn rows between unbounded preceding and 1 following) as TotalQty
      from (values (0, 30),
                   (1, -3),
                   (2, -2),
                   (3, 8)
           ) v (rn, Qty)
     ) t
where changedqty is not null;

Here 是一个 dbfiddle。