How to replace all values in grouped column except first row - sql

Question

I have table like this:
ID Region CreatedDate Value
--------------------------------
1 USA 2016-01-01 5
2 USA 2016-02-02 10
3 Canada 2016-02-02 2
4 USA 2016-02-03 7
5 Canada 2016-03-03 3
6 Canada 2016-03-04 10
7 USA 2016-03-04 1
8 Cuba 2016-01-01 4
I need to sum column Value grouped by Region and CreatedDate by year and month. The result will be
Region Year Month SumOfValue
--------------------------------
USA 2016 1 5
USA 2016 2 17
USA 2016 3 1
Canada 2016 2 2
Canada 2016 3 13
Cuba 2016 1 4
BUT I want to replace all repeated values in column Region with empty string except first met row. The finish result must be:
Region Year Month SumOfValue
--------------------------------
USA 2016 1 5
2016 2 17
2016 3 1
Canada 2016 2 2
2016 3 13
Cuba 2016 1 4
Thank you for a solution. It will be advantage if solution will replace also in column Year

Answer 1

You need to use SUM and GROUP BY to get the SumOfValue. For the formatting, you can use ROW_NUMBER:
WITH Cte AS(
SELECT
Region,
[Year] = YEAR(CreatedDate),
[Month] = MONTH(CreatedDate),
SumOfValue = SUM(Value),
Rn = ROW_NUMBER() OVER(PARTITION BY Region ORDER BY YEAR(CreatedDate), MONTH(CreatedDate))
FROM #tbl
GROUP BY
Region, YEAR(CreatedDate), MONTH(CreatedDate)
)
SELECT
Region = CASE WHEN Rn = 1 THEN c.Region ELSE '' END,
[Year],
[Month],
SumOfValue
FROM Cte c
ORDER BY
c.Region, Rn
ONLINE DEMO
Although this can be done in TSQL, I suggest you do the formatting on the application side.
Query that follows the same order as the OP.