在sql中加入计算

Question

我正在尝试在 sql 2008 的连接中实现交错计算。我可以为 1 个作业 ID 设置 n 行。我在下面创建了一个示例

CREATE TABLE Job
(
  JobID INT NOT NULL,
  Amount INT NOT NULL
);

INSERT INTO Job (JobID, Amount)
    VALUES (1, 25),
        (1, 45),
        (1, 40),
        (2, 25),
        (3, 26),
        (3, 26);

现在JobID = 1 的折扣是 80 ，所以我期望的查询结果输出如下：

如果是 Amount > Discount ，那么显示 finalvalue = Amount - Discount 但如果 Amount < Discount ，则显示 Finalvalue = Amount - Amount ， 如果 Discount 仍然存在，则从后续行中扣除相同的值。

Job ID  Amount  FinalValue
1        25       0
1        45       0
1        40      30

所有这些都可以在一个连接中完成吗？

Answer 1

你在这里：

编辑：注意：您应该添加一列进行排序。我的方法是按 JobID 进行分区和排序，这使得输出随机......

编辑：抱歉，没有添加表格...

CREATE TABLE Job
(
    JobID INT NOT NULL,
    Amount INT NOT NULL
);

INSERT INTO Job (JobID, Amount)
    VALUES (1, 25), (1, 45), (1, 40), (2, 25), (3, 26), (3, 26);

CREATE TABLE Discount
(
    JobID INT NOT NULL,
    Discount INT NOT NULL
);
INSERT INTO Discount(JobID,Discount)VALUES(1,80),(2,0),(3,10);
    WITH myCTE AS
    (
        SELECT ROW_NUMBER() OVER(PARTITION BY Job.JobID ORDER BY Job.JobID) AS inx
              ,Job.JobID
              ,Job.Amount
              ,Discount.Discount     
        FROM Job
        INNER JOIN Discount ON Job.JobID=Discount.JobID
    )
    SELECT * FROM myCTE
    CROSS APPLY
    (
        SELECT SUM(x.Amount)
        FROM myCTE AS x
        WHERE x.JobID=myCTE.JobID
          AND x.inx<=myCTE.inx  
    ) AS AmountCummulativ(AmountCummulativ)
    CROSS APPLY(SELECT AmountCummulativ-myCTE.Discount) AS DiscountCalculated(DiscountCalculated)
    CROSS APPLY(SELECT CASE WHEN DiscountCalculated<0 THEN 0 ELSE DiscountCalculated END) AS DiscountResolved(DiscountResolved)

希望对你有帮助

Answer 2

我认为您要查找的内容可以使用 case 语句来完成

select a.jobid,a.Amount,case when a.amount > b.discount then a.amount - b.discount else 0 end final_value

从Job a 内加入Job_discount b on a.jobid = b.jobid

你可以在这里查看结果http://sqlfiddle.com/#!3/f9a46/1

我不得不假设折扣表结构

Answer 3

我为 Job 表（称为 JobOrder）添加了一些序列（行号），以增加总和。您可以像现在一样更改 JobId、Amount 的顺序！

With JobOrder as (
  -- Job order by id and amount
  select row_number() over (order by JobID, Amount asc) as rowno, JobId, Amount from Job
),
JobSumIncr as (
  select 
  JobID, 
  Amount, 
  (select sum(Amount)
   from JobOrder j2
   where j2.JobID = j.JobID and j2.RowNo <= j.RowNo
  ) as AmountTotal
  from JobOrder j
)
select 
  j.JobID,
  j.Amount,
  j.AmountTotal,
  d.Discount,
  (case when d.Discount>=j.AmountTotal then 0 else j.AmountTotal-d.Discount end) as FinalValue
from
  JobSumIncr j left join Discount d on j.JobID = d.JobID; 

假设您的折扣表类似于：

CREATE TABLE Discount (
    JobID INT,
    Discount INT 
);

SqlFiddle here! 要获得更安全的 Sql（检查 null 值并查看剩余折扣），请参阅此 SQLFiddle too。

跟踪剩余折扣的版本，参见上面的 sqlfiddle-2。