Calculate Page number based on two columns - sql-server

Question

I have the below table I want to find the Page number.
The logic is if the sum of both col A and col b is greater than or equal to 15 then it should be page and it should be incremented.
Col A will be always 1 or 0. Only Col B will changed
Problem :
Col X
Col y
col A
Col B
Pagenumber
x
y
1
105
x
y
1
0
x
y
1
2
x
y
1
6
x
y
1
3
null
y
0
1
x
y
1
2
x
y
1
3
x
y
1
1
x
y
1
4
Expected output :
Col X
Col y
col A
Col B
Pagenumber
x
y
1
105
Page 1
x
y
1
0
Page 2
x
y
1
2
Page 2
x
y
1
6
Page 2
x
y
1
3
Page 2
null
y
0
1
Page 3
x
y
1
2
Page 3
x
y
1
3
Page 3
x
y
1
1
Page 3
x
y
1
4
Page 3
Query without pagenumber column:
SELECT
IIF(c2.isdeleted = 1 OR c2.approved = 0, NULL, c2.content) AS Content,
(SELECT STRING_AGG(c1.content, ', ')
FROM comments c1
WHERE c1.parentcommentid = c2.id
AND c1.isdeleted = 0
AND c1.approved = 1) ChildContent,
IIF(c2.isdeleted = 1 OR c2.approved = 0, 0, 1) AS Contentcount,
(SELECT COUNT(c1.content)
FROM comments c1
WHERE c1.parentcommentid = c2.id
AND c1.isdeleted = 0
AND c1.approved = 1) ChildContentcount
FROM
comments c2
WHERE
c2.discussionid = '402930'
AND c2.parentcommentid IS NULL
-- AND Content IS NOT NULL
ORDER BY
c2.pinned DESC,
c2.createddate

Answer 1

You need to specify the order of rows in which the cumulative sum should be calculated.
You can use a recursive CTE to calculate and partition the running sum.
with t(rn, x, y, a, b) as (
select row_number() over (order by ???), -- set the ordering columns here
x, y, a, b
from your_table
),
cte(rn, x, y, a, b, running_sum, page) as (
select t.rn, t.x, t.y, t.a, t.b, t.a + t.b, 1
from t where rn = 1
union all
select t.rn, t.x, t.y, t.a, t.b,
t.a + t.b + case when cte.running_sum >= 15 then 0 else cte.running_sum end,
case when cte.running_sum >= 15 then cte.page + 1 else cte.page end
from cte join t on t.rn = cte.rn + 1
where t.rn > 1
)
select *
from cte;
Result: