Calculate year over year increase SQL Server 2008R2 - sql

Question

Below is my table structure. I need to calculate rent for length of lease for each properties:
Let's look at PropertyID = 12077:
Area = 1280
StartDate = 2023-02-01
EndDate = 2027-10-31
BaseRent = 21.53
RentIncreasePercent = .04 (4 percent)
IncreaseRepeatMonths = 12 months (NOTE: First 12 months there won't be any increase)
Since this property lease starts and ends between year 2023 and 2028, I'd like to know (in separate row per year) amount of rent to be collected each year. This would take percent increase every 12 months (compound rent increase) into consideration.
Example:
21.53 * 1280 would give rent for first 12 months. However, lease started in February so year 2023 total rent amount would be = ((21.23 * 1280)/12) * 11
For year 2024, first month rent would be = (21.23 * 1280)/12 because rent only increases every 12 months. For next 11 months of 2024, rent would be ((12.23 * 1.04 * 1280)/12)* 11.
For year 2025, first month rent would be (12.23 * 1.04 *1280)/12). However, next 11 months of 2025 would be ((12.72 * 1.04 * 1280)/12)*11. 12.72 comes from compound increase.
How would I go about coming up with a view to do this? Most confusing part to me is not knowing how to accommodate for lease start date when it is not starting on January.
declare #table table
(
PropertyID int,
area int,
StartDate date,
EndDate date,
BaseRent decimal(12,2),
RentIncreaseBasis varchar(30),
RentIncreasePercent decimal(5,2),
IncreaseRepeatMonths int
)
insert #table values (12076, 5627, '2024-01-01', '2028-12-31', '16.52', '% Increase', 0.03, 12)
insert #table values (12077, 1280, '2023-02-01', '2027-10-31', '21.53', '% Increase', 0.04, 12)
insert #table values (12078, 1000, '2017-03-01', '2025-11-30', '23.52', '% Increase', 0.01, 12)
insert #table values (12079, 2000, '2020-02-01', '2024-09-30', '15.57', '% Increase', 0.05, 12)
insert #table values (12080, 3000, '2018-05-01', '2020-08-31', '18.58', '% Increase', 0.04, 12)
insert #table values (12081, 4000, '2019-08-01', '2020-12-31', '22.56', '% Increase', 0.03, 12)
insert #table values (12082, 5000, '2017-02-01', '2028-03-31', '19.53', '% Increase', 0.02, 12)
select * from #table

Answer 1

I recommend to use a calendar table which containts all the months from your table.
I hope my example will work in SQL 2008.
-- here is your code
-- the calendar table
DECLARE #MonthCalendar table(
[Month] date PRIMARY KEY
)
DECLARE #MinDate date,#MaxDate date
-- get min and max date
SELECT
#MinDate=MIN(StartDate),
#MaxDate=MAX(EndDate)
FROM #table
-- fill the calendar table
;WITH monthCTE AS(
SELECT CAST(#MinDate AS date) [Month]
UNION ALL
SELECT DATEADD(MONTH,1,[Month])
FROM monthCTE
WHERE [Month]<#MaxDate
)
INSERT #MonthCalendar([Month])
SELECT [Month]
FROM monthCTE
OPTION(MAXRECURSION 0);
-- final query
SELECT
*,
(BaseRent*Area*(1+RentIncreasePercent*IncreaseCount))/12 MonthRentAmount,
(1+RentIncreasePercent*IncreaseCount) TotalPercent
FROM
(
SELECT *,(ROW_NUMBER()OVER(PARTITION BY t.PropertyID ORDER BY m.[Month])-1)/12 IncreaseCount
FROM #table t
JOIN #MonthCalendar m ON m.[Month] BETWEEN t.StartDate AND t.EndDate
--WHERE t.PropertyID=12077
) q
-- query for total amounts by PropertyIDs and Years
SELECT
PropertyID,
YEAR(StartDate) [Year],
SUM((BaseRent*Area*(1+RentIncreasePercent*IncreaseCount))/12) YearRentAmount
FROM
(
SELECT *,(ROW_NUMBER()OVER(PARTITION BY t.PropertyID ORDER BY m.[Month])-1)/12 IncreaseCount
FROM #table t
JOIN #MonthCalendar m ON m.[Month] BETWEEN t.StartDate AND t.EndDate
--WHERE t.PropertyID=12077
) q
GROUP BY PropertyID,YEAR(StartDate)
ORDER BY PropertyID,[Year]