Løbende total for betalinger til de udstedte fakturaer

with DateRange as
(
  select convert(date, '2020-11-01') as DateValue
  union all
  select dateadd(day, 1, dr.DateValue)
  from DateRange dr
  where dr.DateValue < '2020-11-30'
),
InvoicedTotal as
(
  select dr.DateValue,
         isnull(sum(i.Total), 0) as Invoiced
  from DateRange dr
  left join Invoices i
    on i.InvoiceDate = dr.DateValue
  group by dr.DateValue
),
PaidTotal as
(
  select dr.DateValue,
         isnull(sum(case
                      when i.InvoiceDate between '2020-11-01' and '2020-11-30' -- check if matching invoice was found
                      then p.Total                 -- YES = include Total amount in sum
                      else 0                       -- NO  = exclude total amount from sum
                    end), 0) as Paid
  from DateRange dr
  left join Payments p
    on p.PaymentDate = dr.DateValue
  left join Invoices i
    on  i.InvoiceId = p.InvoiceId -- check for invoice related to payment
  group by dr.DateValue
)
select convert(varchar(10), dr.DateValue, 102) as [YYYY.MM.DD],
       it1.Invoiced as [Invoiced],
       it3.Invoiced as [CumInvoiced],
       pt1.Paid as [Paid],
       pt3.Paid as [CumPaid],
       it3.Invoiced - pt3.Paid as [RunningTotal]
from DateRange dr
join InvoicedTotal it1
  on it1.DateValue = dr.DateValue
join PaidTotal pt1
  on pt1.DateValue = dr.DateValue
cross apply ( select sum(it2.Invoiced) as Invoiced
              from InvoicedTotal it2
              where it2.DateValue <= dr.DateValue ) it3
cross apply ( select sum(pt2.Paid) as Paid
              from PaidTotal pt2
              where pt2.DateValue <= dr.DateValue ) pt3
order by dr.DateValue;

Violin af milo2011