SQL Server 2012 Find bucket wise products and dates - sql

Question

I have a table like below:
date prodname
2018-01-01 Product1
2018-01-05 Product1
2018-01-09 Product1
2018-01-17 Product1
2018-01-24 Product1
2018-01-26 Product1
2018-02-20 Product1
2018-01-02 Product2
2018-01-07 Product2
2018-01-09 Product2
2018-01-17 Product2
2018-01-28 Product2
Code:
CREATE TABLE myTemp(
Date Date,
ProductName varchar(10))
INSERT INTO myTemp values
('2018-01-01', 'Product1')
,('2018-01-05','Product1')
,('2018-01-09','Product1')
,('2018-01-17','Product1')
,('2018-01-24','Product1')
,('2018-01-26','Product1')
,('2018-02-20','Product1')
,('2018-01-02','Product2')
,('2018-01-07','Product2')
,('2018-01-09','Product2')
,('2018-01-17','Product2')
,('2018-01-28','Product2')
The table can have any number of date's entries for each product.
I want to display the product name, minimum date and min date + 24 days. And I want to do this for each 25 days' bucket.
For example,
In case of product1, 2018-01-01 is the min date and 2018-01-25 is the PLUS 25 date.
BUT, product1 also has records for date greater than 2018-01-25. So I should see one more record for product1 in the output like below:
2018-01-26 2018-02-19 product1
2018-01-26 being the Min Date after 2018-01-25. 2109-02-19 being the PLUS 25 date. and product1 is the product name.
That way, my final output should be:
2018-01-01 2018-01-25 Product1
2018-01-26 2018-02-19 Product1
2018-01-02 2018-01-26 Product2
2018-01-28 2018-02-21 Product2
I tried doing it with min() and DateAdd() but it gives me one row for each product.
DROP TABLE IF EXISTS #MyTemp
select MIN(Date) CurrDate, DateAdd(d, 24, MIN(Date)) CurrPlus25Date, ProductName
into #MyTemp
from myTemp
group by ProductName
select * from #MyTemp
Appreciate any help.

Answer 1

Here is one way using recursive cte. If you have a number / tally table, you can simply take the product cte and cross join with the tally table
; with
product as
(
select ProductName,
minDate = min(Date),
maxDate = max(Date)
from myTemp
group by ProductName
),
productdates as
(
select ProductName, minDate, maxDate,
frDate = minDate, toDate = dateadd(day, 24, minDate)
from product
union all
select ProductName, minDate, maxDate,
frDate = dateadd(day, 1, toDate),
toDate = dateadd(day, 25, toDate)
from productdates
where frDate < maxDate
)
select ProductName, frDate, toDate
from productdates
order by ProductName, frDate

Answer 2

This following query will provide your desired output-
SELECT C.min_datre,C.Plus_24_date,C.ProductName
FROM
(
--Select data for the initial Date Range
SELECT MIN(Date) AS min_datre,DATEADD(DD,24,MIN(Date)) AS Plus_24_date,
ProductName
FROM myTemp
GROUP BY ProductName
UNION ALL
--Select Data for Out of first defined range
SELECT MIN(B.Date),
DATEADD(DD,24,MIN(B.Date)),
ProductName
FROM
(
--Select records per product with date greater
--than overall MIN(Date)+24
SELECT
mt.date Date,
mt.ProductName,
A.min_date
FROM myTemp mt
INNER JOIN (
SELECT MIN(Date) min_date,
DATEADD(DD,24,MIN(Date)) with_24_day,
ProductName
FROM myTemp
GROUP BY ProductName
) A
ON mt.ProductName = A.ProductName
AND mt.Date > A.with_24_day
) B
GROUP BY B.ProductName
) C
ORDER BY 3,1