Wrong Opening Balance for some rows - sql

Question

I want to calculate Opening and Closing Balance of a business application. But for some rows wrong Opening Balance is producing. I have following Data Tables:
SupplierPayments
DateOfPayment Bill
2018-06-01 4000
2018-06-01 9000
2018-06-19 2000
2018-06-19 6000
2019-03-28 3000
2019-03-29 5000
Expensis
DateOfExpense Expense
2018-08-14 2,000
2019-02-26 8,000
2019-03-28 2000
2019-03-29 2000
Income
DateSold Income
2018-09-27 24,000
2018-10-17 8,000
2019-01-01 13,000
2019-03-28 10,000
SQL Server 2012 Query
with Income( DateSold, Income ) as (
select DateSold,isnull(sum(TotalBill),0)
from SalesInvoice group by DateSold
), SupplierPayments( DateOfPayment,Bill ) as(
select DateOfPayment,isnull(sum(BillPaidAmount),0)
from SupplyInvoicePaymentHistory group by DateOfPayment
), Expensis( DateOfExpense, Expense ) as(
select Date ,isnull(sum(Amount),0)
from GeneralExpense group by Date
), t as (
select i.DateSold
,e.DateOfExpense
,sp.DateOfPayment
,i.income
, e.Expense
,sp.Bill
, sum(isnull(i.income,0)-(isnull(e.Expense,0)+isnull(sp.Bill,0))) over (order by i.DateSold,e.DateOfExpense,sp.DateOfPayment) as closing_balance
from income i
full outer join expensis e on e.DateOfExpense = i.DateSold
full outer join SupplierPayments sp on sp.DateOfPayment=e.DateOfExpense
)
select m.EventDate, m.DateSold
,m.DateOfExpense
,m.DateOfPayment
,isnull(m.opening_balance,0) as Opening_Balance
,isnull(m.Income,0) as Income
,isnull(m.Expense,0) as Expensis
,isnull(m.Bill,0) as SupplierPayments
,isnull(m.closing_balance,0) as Closing_Balance
from (
select coalesce(coalesce(DateOfPayment, DateOfExpense), DateSold) EventDate, DateSold
,DateOfExpense
,DateOfPayment
,lag(closing_balance,1,0) over (order by DateSold, DateOfExpense,DateOfPayment) as opening_balance
,Income
,Expense
,closing_balance
,Bill
from t
) as m order by m.EventDate ASC
Output
EventDate DateSold ExpenseDate PaymentDate Opening Income Expense Bill Closing
2018-06-01 NULL NULL 2018-06-01 0 0 0 13000 -13000
2018-06-19 NULL NULL 2018-06-19 -13000 0 0 8000 -21000
2018-08-14 NULL 2018-08-14 NULL -21000 0 2000 0 -23000
2018-09-27 2018-09-27 NULL NULL -30000 24000 0 0 -6000
2019-01-01 2019-01-01 NULL NULL -6000 13000 0 0 7000
2019-03-28 2019-03-28 2019-03-28 2019-03-28 7000 10000 2000 3000 12000
2019-03-29 NULL 2019-03-29 2019-03-29 -23000 0 2000 5000 -30000
Formula to calculate closing balance is as:
Closing = Opening + Income - Expense - Bill
As we can notice that opening balance for date 2018-09-27 is -30,000 which is wrong. It should be -23,000. similarly opening balance for date 2019-03-29 is also wrong.
Required Result
EventDate DateSold ExpenseDate PaymentDate Opening Income Expense Bill Closing
2018-06-01 NULL NULL 2018-06-01 0 0 0 13000 -13000
2018-06-19 NULL NULL 2018-06-19 -13000 0 0 8000 -21000
2018-08-14 NULL 2018-08-14 NULL -21000 0 2000 0 -23000
2018-09-27 2018-09-27 NULL NULL -23000 24000 0 0 1000
2019-01-01 2019-01-01 NULL NULL 1000 13000 0 0 14000
2019-03-28 2019-03-28 2019-03-28 2019-03-28 14000 10000 2000 3000 19000
2019-03-29 NULL 2019-03-29 2019-03-29 19000 0 2000 5000 12000
It is possible that in any day there is No item sold but there is expense or bill paid to supplier and vice versa.
Also it is possible that any tables has two entries on the same date.

Answer 1

Your issue lies within the order by columns for both SUM and LAG. If you selected from t CTE alone, you'd see that you're not ordering by whatever is in any of the three dates (what's available), you're ordering by them in the order you specified. So you'll get NULLs for the first column first, NULLs for the second column first, etc. What you need to do is introduce the EventDate sooner, in t, and order everything by it.
;with xIncome( DateSold, Income ) as (
select DateSold,isnull(sum(income),0)
from income group by DateSold
), xSupplierPayments( DateOfPayment,Bill ) as(
select DateOfPayment,isnull(sum(bill),0)
from supplierpayments group by DateOfPayment
), xExpensis( DateOfExpense, Expense ) as(
select DateOfExpense Date ,isnull(sum(expense),0)
from expensis group by Dateofexpense
), t as (
select i.DateSold
,e.DateOfExpense
,sp.DateOfPayment
,consolidated.date consolidatedDate
,i.income
, e.Expense
,sp.Bill
, sum(isnull(i.income,0)-(isnull(e.Expense,0)+isnull(sp.Bill,0))) over (order by consolidated.date) as closing_balance
from xincome i
full outer join xexpensis e on e.DateOfExpense = i.DateSold
full outer join xSupplierPayments sp on sp.DateOfPayment=e.DateOfExpense
cross apply (select coalesce(i.DateSold,e.DateOfExpense,sp.DateOfPayment) as date) consolidated
)
select consolidatedDate, m.DateSold
,m.DateOfExpense
,m.DateOfPayment
,isnull(m.opening_balance,0) as Opening_Balance
,isnull(m.Income,0) as Income
,isnull(m.Expense,0) as Expensis
,isnull(m.Bill,0) as SupplierPayments
,isnull(m.closing_balance,0) as Closing_Balance
from (
select consolidatedDate
,DateSold
,DateOfExpense
,DateOfPayment
,lag(closing_balance,1,0) over (order by consolidatedDate) as opening_balance
,Income
,Expense
,closing_balance
,Bill
from t
) as m order by m.consolidatedDate ASC
Notice the CROSS APPLY in t CTE, where I COALESCE all the dates into a single cosnolidated date. I had to rename the first CTEs to match your sample data table names, but you get the gist of it.