Solved

how to update one record when there are duplicates?

Posted on 1998-08-20
7
171 Views
Last Modified: 2010-03-19
Is there a way to update only one record when there are duplicate records in the table?  
The reason there are duplicates is because the distinct key fields haven't been populated yet, but I need to perform an update on only one particular record before I can fill in the distinct key fields.  Any suggestions?
0
Comment
Question by:Lorik
7 Comments
 
LVL 4

Expert Comment

by:mcix
ID: 1089671
An easy way would be to have an identity field in your table.  On the insert, you could return the @@Identity variable to your code from a stored proc that does the insert.  With that value, you would have a unique criteria for the where clause for the update.

If you can't modify the table struct, there are possibly other ways.
0
 
LVL 10

Expert Comment

by:bret
ID: 1089672
I know this would work in Sybase SQL Server, not sure in MS SQL, but give it a try (on a test table, please!).
-- limit action to a single row
set rowcount 1
go
update mytable
where dupkeyvalue = <x>
go
-- return to affecting full set of rows
set rowcount 0
go

0
 

Author Comment

by:Lorik
ID: 1089673
MS-SQL doesn't have ROWCOUNT funtion, I wish it did.
0
NAS Cloud Backup Strategies

This article explains backup scenarios when using network storage. We review the so-called “3-2-1 strategy” and summarize the methods you can use to send NAS data to the cloud

 
LVL 4

Expert Comment

by:mcix
ID: 1089674
0
 
LVL 1

Accepted Solution

by:
DennisH earned 100 total points
ID: 1089675
SQL Server does not allow selected updates unless there is a primary key designated for a table.
0
 
LVL 5

Expert Comment

by:mayhew
ID: 1089676
Lorik,

I'm not sure I understand exactly what you're trying to do.  If I understand your question, you might want to do an UPDATE...WHERE, something like:

UPDATE table SET <whatever>
WHERE <afield> = (select distinct <afield> from table)

This may give you a starting point, again depending on what exactly you want to do.

Don
0
 
LVL 5

Expert Comment

by:mayhew
ID: 1089677
Lorik,

Sorry, I wasn't thinking straight.  What I wrote before will not work.  Please ignore it.

If you want to update only one row, you have to find something unique about it.  It doesn't have to be a key, but it has to be unique.  

Otherwise you have to do something procedural like using a cursor to find the set, fetch the first record and then update it.  Let us know if you need help with this.  :)

Don
0

Featured Post

Best Practices: Disaster Recovery Testing

Besides backup, any IT division should have a disaster recovery plan. You will find a few tips below relating to the development of such a plan and to what issues one should pay special attention in the course of backup planning.

Question has a verified solution.

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

Let's review the features of new SQL Server 2012 (Denali CTP3). It listed as below: PERCENT_RANK(): PERCENT_RANK() function will returns the percentage value of rank of the values among its group. PERCENT_RANK() function value always in be…
Introduction SQL Server Integration Services can read XML files, that’s known by every BI developer.  (If you didn’t, don’t worry, I’m aiming this article at newcomers as well.) But how far can you go?  When does the XML Source component become …
This videos aims to give the viewer a basic demonstration of how a user can query current session information by using the SYS_CONTEXT function
Viewers will learn how to use the SELECT statement in SQL to return specific rows and columns, with various degrees of sorting and limits in place.

776 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