Get currency exchange rate in SQL - sql-server

Question

Using SQL Server, I have...
AccDocumentItems Table:
SLId DL1Id DL2Id Debit Credit CurId ExchangeRate Cnt
------------------------------------------------------------------------------
S1 D1 D4 2000 0 1 1000 2
S1 D1 D4 0 6000 1 1500 4
S1 D1 D4 6000 0 1 1200 5
S2 D2 D4 4000 0 2 1000 4
S2 D2 D4 0 2000 2 1000 2
S2 D2 D4 3000 0 2 1500 2
I am trying to write a query in sql that group by CurId then substract Cnt column that has debit greater than 0 from Cnt Column that has Debit 0,for example row 1 to 3 has CurId 1 and row 1 has Debit greater than zero,then we have (2-4+5)=3 and row 4 to 6 has CurId 2 then we have (4-2+2)=4 finally I want sum of them 3*Last ExchangeRate in ExchangeRates Table, and 4*Last ExchangeRate in ExchangeRates Table, then sum of (3*Last ExchangeRate+4*Last ExchangeRate).
ExchangeRates Table:
CurrencyId EffectiveDate ExchangeRate
------------------------------------------------
1 2016-1-1 1000
2 2016-1-2 1200
2 2016-1-3 2000
1 2016-1-4 1500
result=(3*Last ExchangeRate+4*Last ExchangeRate)-((sum of Debit)-(sum
of Credit))
in this example Last ExchangeRate for CurrencyId 1 is 1500, and Last ExchangeRate for CurrencyId 2 is 2000 finally I want this result
result=(3*1500+4*2000)-(15000-8000)

Answer 1

This solution is based on your calculations and works only with 2 CurId's.
declare #cur_1 int = 1
declare #cur_2 int = 2
;with AccDocumentItems as (
select
*
from
(values
('S1','D1','D4',2000,0,1,1000,2)
,('S1','D1','D4',0,6000,1,1500,4)
,('S1','D1','D4',6000,0,1,1200,5)
,('S2','D2','D4',4000,0,2,1000,4)
,('S2','D2','D4',0,2000,2,1000,2)
,('S2','D2','D4',3000,0,2,1500,2)
) t (SLId, DL1Id, DL2Id, Debit, Credit, CurId, ExRate, Cnt)
)
, ExchangeRates as (
select
*
from
(values
(1,'2016-1-1',1000)
,(2,'2016-1-2',1200)
,(2,'2016-1-3',2000)
,(1,'2016-1-4',1500)
) t (CurrencyId, EffectiveDate, ParityRate)
)
select
sum(t.cnt * q.ParityRate) - sum(diff)
from
(
select
CurId, diff = sum(Debit) - sum(Credit), cnt = sum(cnt * case when Debit = 0 then -1 else 1 end)
from
AccDocumentItems
where
CurId in (#cur_1, #cur_2)
group by CurId
) t
join (
select
top 1 with ties *
from
ExchangeRates
order by row_number() over (partition by CurrencyId order by EffectiveDate desc)
) q on t.CurId = q.CurrencyId

Answer 2

This solution works for All CurId's.
Declare #Result int
Declare #DeCr int
Declare #Cur int
Set #DeCr = (
Select SUM(Debit)-SUM(Credit)
From dbo.AccDocumentItems
)
Set #Cur =
(
Select Sum(ParityRate * Zarib)
From
(
Select ExchangeRates.CurrencyId as cuur,ParityRate
From
(
Select Max(EffectiveDate) As MaxDate,CurrencyId
From dbo.ExchangeRates
Group by CurrencyId
)As Table1
left join
dbo.ExchangeRates
ON table1.currencyid = ExchangeRates.CurrencyId
And Table1.MaxDate = EffectiveDate
) As Table3
inner join
(
Select Curid
, sum(cnt*signs) As Zarib
From
(
Select CurId
, Cnt
, Case
When Debit = 0 Then -1
Else 1
End As Signs
From dbo.AccDocumentItems
) As Table2
Group by Curid
) As Table4
On Table3.cuur = Table4.Curid
)
Select #Cur - #DeCr

Answer 3

Declare #Result int
Declare #DeCr int
Declare #Cur int
Set #DeCr = (
Select SUM(Debit)-SUM(Credit)
From dbo.AccDocumentItems
)
Set #Cur =
(
Select Sum(ParityRate * Zarib)
From
(
Select ExchangeRates.CurrencyId as cuur,ParityRate
From
(
Select Max(EffectiveDate) As MaxDate,CurrencyId
From dbo.ExchangeRates
Group by CurrencyId
)As Table1
left join
dbo.ExchangeRates
ON table1.currencyid = ExchangeRates.CurrencyId
And Table1.MaxDate = EffectiveDate
) As Table3
inner join
(
Select Curid
, sum(cnt*signs) As Zarib
From
(
Select CurId
, Cnt
, Case
When Debit = 0 Then -1
Else 1
End As Signs
From dbo.AccDocumentItems
) As Table2
Group by Curid
) As Table4
On Table3.cuur = Table4.Curid
)
set #result = #Cur - #DeCr
Select #result