Solved

Subquery on the same table

Posted on 2013-06-20
2
269 Views
Last Modified: 2013-06-20
I have a table with four columns

Code
Value
Rank
RollingValue

I want to update the RollingValue to the Value plus the Value in the previous Rank
Initially all the values in the RollingVale are zero

Code   Value      Rank       RollingValue
ABCD   7            1            0
ABCD   21       2            0
ABCD   10            3            0


Code   Value      Rank       RollingValue
ABCD   7            1            7
ABCD   21       2            28
ABCD   10            3            38

I tried this

         UPDATE TableT
        SET RollingValue = t.Value + p.Value  
        FROM  TableT  t
        INNER JOIN
       ( Select Code, Value, Rank from TableT) AS  p        
        ON t.Code = p.Code
        WHERE (t.Rank = (p.Rank + 1))
0
Comment
Question by:countrymeister
  • 2
2 Comments
 
LVL 11

Expert Comment

by:Louis01
ID: 39263371
declare @TableT TABLE (Code char(4) not null
                      ,Value int not null
                      ,[Rank] int not null
                      ,RollingValue int not null)

insert into @TableT (Code,Value,[Rank],RollingValue) values ('ABCD', 7, 1, 0)
insert into @TableT (Code,Value,[Rank],RollingValue) values ('ABCD', 21, 2, 0)
insert into @TableT (Code,Value,[Rank],RollingValue) values ('ABCD', 10, 3, 0)

update t1
   set t1.RollingValue = (select SUM(t2.Value) 
                            from @TableT t2
                           where t2.[Rank] <= t1.[Rank])
  from @TableT t1

select * from @TableT

Open in new window

0
 
LVL 11

Accepted Solution

by:
Louis01 earned 500 total points
ID: 39263375
Example of how you'll select it:
select t2.Code
     , t2.Value
     , t2.[Rank]
     , SUM(t1.Value) as RollingValue
  from @TableT t1 right outer join @TableT t2
    on t1.[Rank] <= t2.[Rank]
 group by t2.Code
        , t2.Value
        , t2.[Rank]
 order by t2.[Rank]

Open in new window

0

Featured Post

U.S. Department of Agriculture and Acronis Access

With the new era of mobile computing, smartphones and tablets, wireless communications and cloud services, the USDA sought to take advantage of a mobilized workforce and the blurring lines between personal and corporate computing resources.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Use this article to create a batch file to backup a Microsoft SQL Server database to a Windows folder.  The folder can be on the local hard drive or on a network share.  This batch file will query the SQL server to get the current date & time and wi…
JSON is being used more and more, besides XML, and you surely wanted to parse the data out into SQL instead of doing it in some Javascript. The below function in SQL Server can do the job for you, returning a quick table with the parsed data.
Using examples as well as descriptions, and references to Books Online, show the documentation available for datatypes, explain the available data types and show how data can be passed into and out of variables.
Viewers will learn how the fundamental information of how to create a table.

911 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

21 Experts available now in Live!

Get 1:1 Help Now