How to find sum of values of previous dates - sql-server

Question

I have 3 columns in Invoice table.
InvoicePeriod
InvoiceType
Fees
I have data like this:
InvoicePeriod InvoiceType Fees
2020-06-30 ABC 10.0
2020-06-30 ABC 40.0
2020-06-30 ABC 32.0
2020-09-30 ABC 5.0
2020-09-30 XYZ 30.0
2020-12-31 ABC 20.0
2020-12-31 ABC 10.0
2021-01-31 XYZ 60.0
2021-02-01 DEF 36.0
Now I want the last(max) of invoice period of each invoice type and the summation of fees of previous dates.
Output:
InvoicePeriod InvoiceType Fees
2020-12-31 ABC 87.0
2021-01-31 XYZ 30.0
2021-02-01 DEF 0.0
How can I achieve this?
Thanks,
Ankit

Answer 1

You want to group by InvoiceType (since you want one row per type) and you want the aggregate functions max and sum to combine values within those groups.
So
SELECT MAX(InvoicePeriod), InvoiceType, SUM(Fees)
FROM mytable
GROUP BY InvoiceType
Edited to exclude the fees that match the max date, now that I understand the problem better:
SELECT t2.MaxPeriod, t2.InvoiceType, SUM(CASE WHEN t1.InvoicePeriod < t2.MaxPeriod THEN t1.Fees ELSE 0 END)
FROM test t1 INNER JOIN
(
SELECT MAX(InvoicePeriod) MaxPeriod, InvoiceType
FROM test
GROUP BY InvoiceType
) t2 ON t1.InvoiceType = t2.InvoiceType
GROUP BY t2.MaxPeriod, t2.InvoiceType
There are different ways of doing this, but I think the above does what you want so you could build off of it. The inner query gets the max InvoicePeriod for each InvoiceType. The outer query uses that and also sums the Fees when the date is less than the max for that group.

Answer 2

I think this is what you're looking for.
SELECT
MAX(in_main.InvoicePeriod) AS InvoicePeriod
, InvoiceType
/* Subtract out fees on last invoice date*/
, SUM(Fees) - (
SELECT COALESCE(SUM(Fees), 0)
FROM Invoice in_sub
WHERE (
in_sub.InvoiceType = in_main.InvoiceType
AND
in_sub.InvoicePeriod = MAX(in_main.InvoicePeriod)
)
) AS Fees
FROM Invoice in_main
GROUP BY InvoiceType
http://sqlfiddle.com/#!18/288adf/2/0

Answer 3

Steps:
Aggregate per period and type.
Get the sum of a type's previous periods.
Use TOP WITH TIES in combination with ROW_NUMBER in order to keep all types' last periods.
The query:
select top(1) with ties
invoiceperiod,
invoicetype,
coalesce(sum(sum(fees)) over (
partition by invoicetype
order by invoiceperiod
rows between unbounded preceding and 1 preceding
), 0.0) as sum_fees
from invoice
group by invoiceperiod, invoicetype
order by row_number() over (partition by invoicetype order by invoiceperiod desc);
Demo: https://dbfiddle.uk/?rdbms=sqlserver_2019&fiddle=6a651f85961b27be687026c2ce73c8f9