SQL 运行分区组的余额计算

Question

我有将数量限制在一定水平的要求。以下数据已分区，还提供了行号。请参考下面这是table

中的当前数据

但是输出应该是这样的。请参考以下内容。

当前卡车容量为 16 辆。但是，如果您看到分区级别的总分配数量为 17。因此我们需要在行级别动态地从最终分配数量中减去额外的 1 数量，最好从 Rownumber 1..2..3 像这样。我曾尝试使用 while 循环完成 运行 总计，但没有成功

到目前为止我已经尝试过什么

DECLARE @GroupCount INT
SET @GroupCount = (SELECT MAX(PartitionNum) FROM Allocation_Table) 
DECLARE @RowCount INT

-- Declare an iterator
DECLARE @I INT,@J int
 --Initialize the iterator
SET @I =1


WHILE (@I <= @GroupCount)
BEGIN
SET @RowCount = (SELECT MAX(RowNumber) FROM Allocation_Table WHERE PartitionNum=@I)  
DECLARE @BS float=0
SELECT @BS = cast([Remainder Qty to be dropped] as float) FROM Allocation_Table WHERE PartitionNum=@I 
SET @J = 1

WHILE (@J <= @RowCount)
BEGIN
        
--PRINT @I

declare @BV float, @Qty float,@flg bit,@Ibs float, @EV float

SELECT @Qty=[Final Allocation Qty] FROM Allocation_Table WHERE PartitionNum=@I and RowNumber=@J 
set @IBS=@BS
SET @BS=case when (@BS>=@Qty) then  @BS-@Qty  else @BS end

SET @flg=case when (@IBS>=@Qty) then  1  when (@IBS<@Qty) and @IBS>0 then  1 else 0 end

set @BS= case when (@IBS<@Qty)  then 0 else @BS end 

update Allocation_Table set BS_Cal=@BS ,Flag=@flg WHERE  RowNumber = @J and PartitionNum=@I 


SET @J = @J + 1
END
SET @I = @I + 1

Answer 1

与评论中所说的相反，使用 window 函数是很有可能的，只是有点复杂。

假设我正确理解了您的情况，您希望按照 RowNumber 的顺序从 material 中删除项目，直到达到 Truck capacity。为此，只需要根据上一行中的值进行一些 运行 聚合和条件数学运算：

查询

declare @t table(pn int,rn int,Material varchar(100),Allocation int,Capacity int);
insert into @t values
 (1,1,'abc',4,16)
,(1,2,'bac',9,16)
,(1,3,'cab',4,16)
,(2,1,'abc',4,12)
,(2,2,'bac',9,12)
,(2,3,'cab',4,12)
,(3,1,'abc',4,2)
,(3,2,'bac',9,2)
,(3,3,'cab',4,2)
,(4,1,'abc',14,112)
,(4,2,'bac',19,112)
,(4,3,'cab',14,112)
,(5,1,'abc',140,112)
,(5,2,'bac',19,112)
,(5,3,'cab',14,112)
;

with d as
(
    select *
          ,sum(Allocation) over (partition by pn) as TotalAllocation
          ,sum(Allocation) over (partition by pn) - Capacity as TotalOverage
          ,sum(Allocation) over (partition by pn)
            - Capacity
            - sum(Allocation) over (partition by pn order by rn)
            as Overage
    from @t
)
select pn
      ,rn
      ,Material
      ,Capacity
      ,TotalAllocation
      ,Allocation
      ,case when Overage > 0
            then 0
            else case when lag(Overage,1) over (partition by pn order by rn) is null
                      then case when Allocation < (Allocation - TotalOverage)
                                then Allocation
                                else Allocation - TotalOverage
                                end
                      else 
                            case when lag(Overage,1,0) over (partition by pn order by rn) > 0
                                      then Allocation - lag(Overage,1,0) over (partition by pn order by rn)
                                      else Allocation
                                      end
                      end
            end as AdjustedAllocation
from d
order by pn
        ,rn;

---

输出

pn	rn	Material	Capacity	TotalAllocation	Allocation	AdjustedAllocation
1	1	abc	16	17	4	3
1	2	bac	16	17	9	9
1	3	cab	16	17	4	4
2	1	abc	12	17	4	0
2	2	bac	12	17	9	8
2	3	cab	12	17	4	4
3	1	abc	2	17	4	0
3	2	bac	2	17	9	0
3	3	cab	2	17	4	2
4	1	abc	112	47	14	14
4	2	bac	112	47	19	19
4	3	cab	112	47	14	14
5	1	abc	112	173	140	79
5	2	bac	112	173	19	19
5	3	cab	112	173	14	14