Cumulative sum of a column - sql

Question

I have a table that has the below data.
COUNTRY LEVEL NUM_OF_DUPLICATES
US 9 6
US 8 24
US 7 12
US 6 20
US 5 39
US 4 81
US 3 80
US 2 430
US 1 178
US 0 430
I wrote a query that will calculate the sum of cumulative rows and got the below output .
COUNTRY LEVEL NUM_OF_DUPLICATES POOL
US 9 6 6
US 8 24 30
US 7 12 42
US 6 20 62
US 5 39 101
US 4 81 182
US 3 80 262
US 2 130 392
US 1 178 570
US 0 254 824
Now I want to to filter the data and take only where the POOL <=300, if the POOL field does not have the value 300 then I should take the first value after 300. So, in the above example we do not have the value 300 in the field POOL, so we take the next immediate value after 300 which is 392. So I need a query so that I can pull the records POOL <= 392(as per the example above) which will yield me the output as
COUNTRY LEVEL NUM_OF_DUPLICATES POOL
US 9 6 6
US 8 24 30
US 7 12 42
US 6 20 62
US 5 39 101
US 4 81 182
US 3 80 262
US 2 130 392
Please let me know your thoughts. Thanks in advance.

Answer 1

declare #t table(Country varchar(5), Level int, Num_of_Duplicates int)
insert into #t(Country, Level, Num_of_Duplicates)
values
('US', 9, 6),
('US', 8, 24),
('US', 7, 12),
('US', 6, 20),
('US', 5, 39),
('US', 4, 81),
('US', 3, 80),
('US', 2, 130/*-92*/),
('US', 1, 178),
('US', 0, 430);
select *, sum(Num_of_Duplicates) over(partition by country order by Level desc),
(sum(Num_of_Duplicates) over(partition by country order by Level desc)-Num_of_Duplicates) / 300 as flag,--any row which starts before 300 will have flag=0
--or
case when sum(Num_of_Duplicates) over(partition by country order by Level desc)-Num_of_Duplicates < 300 then 1 else 0 end as startsbefore300
from #t;
select *
from
(
select *, sum(Num_of_Duplicates) over(partition by country order by Level desc) as Pool
from #t
) as t
where Pool - Num_of_Duplicates < 300 ;

Answer 2

The logic here is quite simple:
Calculate the running sum POOL value up to the current row.
Filter rows so that the previous row's total is < 300, you can either subtract the current row's value, or use a second sum
If the total up to the current row is exactly 300, the previous row will be less, so this row will be included
If the current row's total is more than 300, but the previous row is less then it will also be included
All higher rows are excluded
It's unclear what ordering you want. I've used NUM_OF_DUPLICATES column ascending, but you may want something else
SELECT
COUNTRY,
LEVEL,
NUM_OF_DUPLICATES,
POOL
FROM (
SELECT *,
POOL = SUM(NUM_OF_DUPLICATES) OVER (ORDER BY NUM_OF_DUPLICATES ROWS UNBOUNDED PRECEDING)
-- alternative calculation
-- ,POOLPrev = SUM(NUM_OF_DUPLICATES) OVER (ORDER BY NUM_OF_DUPLICATES ROWS UNBOUNDED PRECEDING AND 1 PRECEDING)
FROM YourTable
) t
WHERE POOL - NUM_OF_DUPLICATES < 300;
-- you could also use POOLPrev above

Answer 3

I used two temp tables to get the answer.
DECLARE #t TABLE(Country VARCHAR(5), [Level] INT, Num_of_Duplicates INT)
INSERT INTO #t(Country, Level, Num_of_Duplicates)
VALUES ('US', 9, 6),
('US', 8, 24),
('US', 7, 12),
('US', 6, 20),
('US', 5, 39),
('US', 4, 81),
('US', 3, 80),
('US', 2, 130),
('US', 1, 178),
('US', 0, 254);
SELECT
Country
,Level
, Num_of_Duplicates
, SUM (Num_of_Duplicates) OVER (ORDER BY id) AS [POOL]
INTO #temp_table
FROM
(
SELECT
Country,
level,
Num_of_Duplicates,
ROW_NUMBER() OVER (ORDER BY country) AS id
FROM #t
) AS A
SELECT
[POOL],
ROW_NUMBER() OVER (ORDER BY [POOL] ) AS [rank]
INTO #Temp_2
FROM #temp_table
WHERE [POOL] >= 300
SELECT *
FROM #temp_table WHERE
[POOL] <= (SELECT [POOL] FROM #Temp_2 WHERE [rank] = 1 )
DROP TABLE #temp_table
DROP TABLE #Temp_2