将第一行十进制值添加到 SQL Server 中的下一行

Question

I have table, as below and its contains customer electricity volume for the period as. Available data like

OwnerID StartDate   EndDate     Volume
---------------------------------------
 1      2019-01-01  2019-01-15  10.40
 1      2019-01-16  2019-01-31   5.80
 1      2019-02-01  2019-02-10   7.90
 1      2019-02-11  2019-02-28   8.50 

For this OwnerID = 1 , having existing some volume 0.90. This should apply first row (add)

1. Get the whole number and decimal part value
2. the first row returned decimal value should add to next row and vice vera.

ExistingVolume - 0.90

So expected result set should like:

OwnerId StartDate   EndDate     CalulatedVolume  AppliedExistingVolume(0.90)   RemainExistingVolume 
----------------------------------------------------------------------------------------------------
    1   2019-01-01  2019-01-15         11                0.60                   0.30
    1   2019-01-16  2019-01-31          6                0.20                   0.10
    1   2019-02-01  2019-02-10          8                0.10                   0.00
    1   2019-02-11  2019-02-28          8                0.00                   0.50 

Could you someone suggest how to achieve this is in SQL query?

Answer 1

The example below uses a cumulative sum and a few CTE's to calculate those 2 columns.

Sample data:

 create table yourtable ( Id int identity(1,1) primary key, OwnerID int not null, StartDate date not null, EndDate date not null, Volume decimal(16,2) not null ); insert into yourtable (OwnerID, StartDate, EndDate, Volume) values (1, '2019-01-01', '2019-01-15', 10.40) , (1, '2019-01-16', '2019-01-31', 5.80) , (1, '2019-02-01', '2019-02-10', 7.90) , (1, '2019-02-11', '2019-02-28', 8.50) ;

Query:

 ;with CTE_EXISTING_VOLUMES AS ( select * from (values (1, 0.9) ) q(OwnerId, ExistingVolume) ) , CTE_DATA AS ( select t.*, c.ExistingVolume , ceiling(t.Volume) - t.Volume as VolumeRemainder , sum(ceiling(t.Volume) - t.Volume) over (partition by t.OwnerID order by t.StartDate) as CumSumVolumeRemainder from yourtable t left join CTE_EXISTING_VOLUMES c on t.OwnerID = c.OwnerID ) , CTE_DATA2 AS ( select * , ceiling(Volume) as CalculatedVolume , IIF(ExistingVolume < CumSumVolumeRemainder, 0.0, (ceiling(Volume) - Volume)) as AppliedExistingVolume from CTE_DATA ) select OwnerId, StartDate, EndDate , CalculatedVolume , AppliedExistingVolume , case when AppliedExistingVolume > 0 then ExistingVolume - CumSumVolumeRemainder else VolumeRemainder end as RemainExistingVolume from CTE_DATA2; GO

\nOwnerId | StartDate | EndDate | CalculatedVolume | AppliedExistingVolume | RemainExistingVolume\n------: |  :------------------ |  :------------------ |  :--------------- |  :-------------------- |  :------------------- \n      1 |  01/01/2019 00:00:00 |  15/01/2019 00:00:00 |  11 |  0.60 |  0.30                 \n      1 |  16/01/2019 00:00:00 |  31/01/2019 00:00:00 |  6 |  0.20 |  0.10                 \n      1 |  01/02/2019 00:00:00 |  10/02/2019 00:00:00 |  8 |  0.10 |  0.00                 \n      1 |  11/02/2019 00:00:00 |  28/02/2019 00:00:00 |  9 |  0.00 |  0.50                 \n

db<>fiddle here

Answer 2

When requirement is absolutely clear then you can think of better solution ie Set Based Approach

When requirement is not so clear then you think of solution like RBAR .

Suppose I was to calculate the output in Excel then what formula I will apply ?

There have to have some formula but requirement is not clear.

create table #temp(OwnerID int, StartDate date,EndDate date,Volume decimal(5,2))
insert into #temp values
  (1,'2019-01-01','2019-01-15', 10.40)
 ,(1,'2019-01-16','2019-01-31', 5.80)
 ,(1,'2019-02-01','2019-02-10', 7.90)
 ,(1,'2019-02-11','2019-02-28', 8.50) 

 declare @ExistingVolume decimal(5,2)=0.90

 ;with CTE as
 (
  select *
 ,ROW_NUMBER()over(partition by ownerid order by startdate)rn 
  from #temp 
  ),
  CTE1 as
  (
  select ownerid
  ,startdate,enddate,Volume
  ,Cast((c.Volume+@ExistingVolume) as int)  CalulatedVolume
  ,Cast((c.Volume+@ExistingVolume) as int)-c.Volume as AppliedExistingVolume
  ,cast((c.Volume+@ExistingVolume-
  cast((c.Volume+@ExistingVolume) as int) )as decimal(5,2)) as RemainExistingVolume
 ,rn
  from CTE C where rn=1 

  union all

  select c.ownerid
  ,c.startdate,c.enddate,c.Volume
  ,cast((c.Volume+c1.RemainExistingVolume) as int) as CalulatedVolume
   ,cast((c.Volume+c1.RemainExistingVolume) as int)-c.Volume as AppliedExistingVolume
  ,cast(((c.Volume+c1.RemainExistingVolume)
  -cast((c.Volume+c1.RemainExistingVolume) as int)) as decimal(5,2))
  ,c.rn
  from CTE C 
  inner join CTE1 C1 on c.OwnerID=c1.OwnerID
  where c.rn=c1.rn+1 
  )



  select ownerid, 
  startdate,enddate
  ,CalulatedVolume
  ,case when AppliedExistingVolume<0 then 0 
  else AppliedExistingVolume end as AppliedExistingVolume
  ,RemainExistingVolume
  from CTE1


 drop table #temp