Select SUM by each year in SQL query - sql

Question

I have these two tables:
Expense table
id expense expense_date product_id
1 10 2012-01-03 1
2 10 2014-02-01 2
3 10 2014-02-03 1
4 10 2012-07-03 1
Product table
product_id product_name purchase_date
1 car 2010-02-01
2 bike 2014-03-01
I would like to achieve the result to something like this by summing the expenses grouping by product_id where the the expense_date is between the purchase_date to it's next year:
Year Expense Product_name
1 0 car 2010-02-01 to 2011-02-01
2 10 car 2011-02-01 to 2012-02-01
3 10 car 2012-02-01 to 2013-02-01
4 0 car 2013-02-01 to 2014-02-01
5 10 car 2014-02-01 to 2015-02-01
1 10 bike 2014-03-01 to 2015-03-01

Answer 1

CREATE VIEW dbo.vwMaxExpenseDate
AS
SELECT product_id, MAX(expense_date) AS 'max_expense_date'
FROM Expense
GROUP BY product_id
DECLARE #PossibleYearRange TABLE
(
product_id INT,
YearStart DATETIME,
YearEnd DATETIME
);
WITH CTE
AS
(
SELECT p.product_id, max_expense_date, purchase_date, 1 As Number
FROM Product p
LEFT JOIN vwMaxExpenseDate e
ON p.product_id = e.product_id
UNION ALL
SELECT product_id, max_expense_date, purchase_date, Number + 1
FROM CTE
WHERE Number <= (YEAR(max_expense_date) - YEAR(purchase_date))
)
INSERT INTO #PossibleYearRange
(
product_id,
YearStart,
YearEnd
)
SELECT product_id,
CONVERT(DATETIME, CONVERT(VARCHAR(20), YEAR(purchase_date) + Number - 1) + '-'
+ CONVERT(VARCHAR(20), MONTH(purchase_date)) + '-'
+ CONVERT(VARCHAR(20), DAY(purchase_date))) AS 'YearStart',
CONVERT(DATETIME, CONVERT(VARCHAR(20), YEAR(purchase_date) + Number) + '-'
+ CONVERT(VARCHAR(20), MONTH(purchase_date)) + '-'
+ CONVERT(VARCHAR(20), DAY(purchase_date))) AS 'YearEnd'
FROM CTE
ORDER BY product_id ASC, NUMBER ASC
SELECT MAX(p.product_id) AS product_id, MAX(product_name) AS product_name, YearStart, YearEnd, COALESCE(SUM(expense), 0) AS TotalExpensePerYear
FROM #PossibleYearRange p
LEFT JOIN Expense e
ON p.product_id = e.product_id AND
expense_date BETWEEN YearStart AND YearEnd
INNER JOIN Product d
ON p.product_id = d.product_id
GROUP BY YearStart, YearEnd
ORDER BY MAX(p.product_id) ASC
Hope this helps! Thanks.

Answer 2

declare #BeginsAt as datetime
declare #numOf as int
set #BeginsAt = (select min(purchase_date) from Products)
set #BeginsAt = dateadd(year,datediff(year,0,#BeginsAt),0) -- force to 1st of Year
set #numOf = (year(getdate()) - year(#BeginsAt))+1
;with YearRange (id, StartAt, StopAt)
as (
select 1 as id, #BeginsAt, dateadd(Year,1,#BeginsAt)
union all
select (id + 1) , dateadd(Year,1,StartAt) , dateadd(Year,1,StopAt)
from YearRange
where (id + 1) <= #numOf
)
select
y.id
, coalesce(e.expense,0) expense
, p.product_name
, y.startAt
, dateadd(day,-1,y.StopAt)
from YearRange Y
left join Products P on Y.StopAt between P.purchase_date AND (select max(StopAt) from YearRange)
left join Expenses E on E.expense_date >= Y.StartAt and E.expense_date < Y.StopAt
and E.product_id = P.product_id
See this SQLFiddle demo