Question

Possible Duplicate:
How do I calculate a running total in SQL without using a cursor?

It’s a little difficult to explain, so I’ll show what I want with an example:

Lets say we have the following table named MonthProfit:

[MonthId][Profit]
1, 10 -- January
2, 20 -- February
3, 30
4, 40
5, 50
6, 60
7, 70
8, 80
9, 90
10, 100
11, 110
12, 120 -- December

Column profit represents the profit for that month.

However, if we have 10 profit in January, and 20 in February, in February we have a total profit of 30.

so I’d like to create a view that shows the following:

[MonthId][Profit][ProfitTotal]
1, 10, 10 -- January
2, 20, 30 -- February
3, 30, 60
4, 40, 100
5, 50, 150
6, 60, 210
7, 70, 280
8, 80, 360
9, 90, 450
10, 100, 550
11, 110, 660
12, 120, 780 -- December

What I did now to solve it, is a view like this:

SELECT [MonthId]
       ,[Profit]
       , (SELECT SUM([Profit])
         FROM MonthProfit
         WHERE [MonthId] <= outer.[MonthId]) as ProfitTotal
FROM MonthProfit as outer

However, I assume this is pretty slow because it has to recount everything all the time, and it does not seem very elegant to me. Is there a “good” way to do this?

Answer 1

I have tried a small example here for your reference this generates the results as per the requirements

CREATE TABLE [dbo].[tbl_TotalPrevious](
[id] [int] IDENTITY(1,1) NOT NULL,
[name] [varchar](50) NOT NULL,
[values] [bigint] NOT NULL) 

INSERT DATA INTO THE TABLE

insert into tbl_TotalPrevious values ('A', 10)
insert into tbl_TotalPrevious values ('B', 20)
insert into tbl_TotalPrevious values ('C', 10)
insert into tbl_TotalPrevious values ('D', 10)
insert into tbl_TotalPrevious values ('E', 10)
insert into tbl_TotalPrevious values ('F', 10)
insert into tbl_TotalPrevious values ('G', 10)
insert into tbl_TotalPrevious values ('H', 10)
insert into tbl_TotalPrevious values ('I', 10)
insert into tbl_TotalPrevious values ('J', 10)
insert into tbl_TotalPrevious values ('K', 10)
insert into tbl_TotalPrevious values ('L', 10)
insert into tbl_TotalPrevious values ('M', 10)
insert into tbl_TotalPrevious values ('N', 10)
insert into tbl_TotalPrevious values ('O', 10)
insert into tbl_TotalPrevious values ('P', 10)
insert into tbl_TotalPrevious values ('Q', 10)
insert into tbl_TotalPrevious values ('R', 10)
insert into tbl_TotalPrevious values ('S', 10)
insert into tbl_TotalPrevious values ('T', 10)
insert into tbl_TotalPrevious values ('U', 10)
insert into tbl_TotalPrevious values ('V', 10)
insert into tbl_TotalPrevious values ('W', 10)
insert into tbl_TotalPrevious values ('X', 10)
insert into tbl_TotalPrevious values ('Y', 10)

Create a Function eg.

ALTER FUNCTION testtotal 
(
    @id int
)
RETURNS int
AS
BEGIN
    DECLARE @Result int
    SELECT @Result = (SELECT SUM([values])
         FROM tbl_TotalPrevious
         WHERE [id] <= @id)

    RETURN @Result

END
GO

RESULTS GENERATED FROM A SINGLE QUERY

SELECT [id],[values], (dbo.testtotal(id)) as TotalVals FROM tbl_TotalPrevious 

HOPE THE ABOVE SOLVES YOUR PURPOSE WITH THE TIMING ISSUE AND GENERATES THE DATA FASTER AS REQUIRED.