How to get cumulative sum

Question

declare  @t table
    (
        id int,
        SomeNumt int
    )

insert into @t
select 1,10
union
select 2,12
union
select 3,3
union
select 4,15
union
select 5,23         


        

Answer 1

The SQL solution wich combines "ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW" and "SUM" did exactly what i wanted to achieve. Thank you so much!

If it can help anyone, here was my case. I wanted to cumulate +1 in a column whenever a maker is found as "Some Maker" (example). If not, no increment but show previous increment result.

So this piece of SQL:

SUM( CASE [rmaker] WHEN 'Some Maker' THEN  1 ELSE 0 END) 
OVER 
(PARTITION BY UserID ORDER BY UserID,[rrank] ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) AS Cumul_CNT

Allowed me to get something like this:

User 1  Rank1   MakerA      0  
User 1  Rank2   MakerB      0  
User 1  Rank3   Some Maker  1  
User 1  Rank4   Some Maker  2  
User 1  Rank5   MakerC      2
User 1  Rank6   Some Maker  3  
User 2  Rank1   MakerA      0  
User 2  Rank2   SomeMaker   1  

Explanation of above: It starts the count of "some maker" with 0, Some Maker is found and we do +1. For User 1, MakerC is found so we dont do +1 but instead vertical count of Some Maker is stuck to 2 until next row. Partitioning is by User so when we change user, cumulative count is back to zero.

I am at work, I dont want any merit on this answer, just say thank you and show my example in case someone is in the same situation. I was trying to combine SUM and PARTITION but the amazing syntax "ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW" completed the task.

Thanks! Groaker

Answer 2

select t1.id, t1.SomeNumt, SUM(t2.SomeNumt) as sum
from @t t1
inner join @t t2 on t1.id >= t2.id
group by t1.id, t1.SomeNumt
order by t1.id

SQL Fiddle example

Output

| ID | SOMENUMT | SUM |
-----------------------
|  1 |       10 |  10 |
|  2 |       12 |  22 |
|  3 |        3 |  25 |
|  4 |       15 |  40 |
|  5 |       23 |  63 |

Edit: this is a generalized solution that will work across most db platforms. When there is a better solution available for your specific platform (e.g., gareth's), use it!

Answer 3

The latest version of SQL Server (2012) permits the following.

SELECT 
    RowID, 
    Col1,
    SUM(Col1) OVER(ORDER BY RowId ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) AS Col2
FROM tablehh
ORDER BY RowId

or

SELECT 
    GroupID, 
    RowID, 
    Col1,
    SUM(Col1) OVER(PARTITION BY GroupID ORDER BY RowId ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) AS Col2
FROM tablehh
ORDER BY RowId

This is even faster. Partitioned version completes in 34 seconds over 5 million rows for me.

Thanks to Peso, who commented on the SQL Team thread referred to in another answer.

Answer 4

There is a much faster CTE implementation available in this excellent post: http://weblogs.sqlteam.com/mladenp/archive/2009/07/28/SQL-Server-2005-Fast-Running-Totals.aspx

The problem in this thread can be expressed like this:

    DECLARE @RT INT
    SELECT @RT = 0

    ;
    WITH  abcd
            AS ( SELECT TOP 100 percent
                        id
                       ,SomeNumt
                       ,MySum
                       order by id
               )
      update abcd
      set @RT = MySum = @RT + SomeNumt
      output inserted.*

Answer 5

Try this

select 
    t.id,
    t.SomeNumt, 
    sum(t.SomeNumt) Over (Order by t.id asc Rows Between Unbounded Preceding and Current Row) as cum
from 
    @t t 
group by
    t.id,
    t.SomeNumt
order by
    t.id asc;

Answer 6

Once the table is created -

select 
    A.id, A.SomeNumt, SUM(B.SomeNumt) as sum
    from @t A, @t B where A.id >= B.id
    group by A.id, A.SomeNumt

order by A.id