Go Premium for a chance to win a PS4. Enter to Win

x
?
Solved

Easy Table Update Question

Posted on 2006-06-13
4
Medium Priority
?
202 Views
Last Modified: 2006-11-18
Hello everyone,

I am using MS SQL 2000 and I actually had a question about the below piece of SQL code.  I guess I am having trouble grasping how it works (and whether it does what I intend to do).  

update Table A
set someColumn = 'Yes'
where id in (select id from Table B)
and date in (select date from Table B)
and someColumn is null

What I really want to do is to set someColumn to 'Yes' only when the id and date on the same row match the id and date from Table B also on a single row.  Each id could occur multiple times in either table with different dates.  However, I am worried that SQL Server might pick an id and a date from separate rows in Table B and update someColumn to 'Yes' in Table A since that combination happened to fall on one row.  Is that what's happening here?  

My apologies if the question above was unclear in any way.  I'd be happy to explain in greater detail if necessary.  Thanks for all your help!
0
Comment
Question by:sviriyal
  • 2
4 Comments
 
LVL 43

Accepted Solution

by:
TimCottee earned 400 total points
ID: 16894330
Hi sviriyal,

Yes is the simple answer, it will match providing there is a row matching the id and a row matching the date in table B. These need not necessarily be the same row.

You need:

Update TableA Set SomeColumn = 'Yes' From TableA Inner Join TableB On TableA.ID = TableB.ID and TableA.Date = TableA.Date Where TableA.SomeColumn Is Null

Though I assume these are not the real field names, you should be aware that "Date" is a reserved word and not advised to be used for naming your column.

Tim Cottee
0
 
LVL 143

Expert Comment

by:Guy Hengel [angelIII / a3]
ID: 16894338
update Table A
set someColumn = 'Yes'
from tableA
JOIN tableB
  on tableA.id =TableB.id
and tabeA.date = tableB.date
and someColumn is null
0
 

Author Comment

by:sviriyal
ID: 16894468
Thank you both for your comments.  However, since Tim was the first to respond with a working answer, I think the points should go to him.  Any objections angelIII?
0
 
LVL 143

Expert Comment

by:Guy Hengel [angelIII / a3]
ID: 16894487
no objects, as additional information (reserved words) were given.
Glad we could help
0

Featured Post

Fill in the form and get your FREE NFR key NOW!

Veeam is happy to provide a FREE NFR server license to certified engineers, trainers, and bloggers.  It allows for the non‑production use of Veeam Agent for Microsoft Windows. This license is valid for five workstations and two servers.

Question has a verified solution.

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

A Stored Procedure in Microsoft SQL Server is a powerful feature that it can be used to execute the Data Manipulation Language (DML) or Data Definition Language (DDL). Depending on business requirements, a single Stored Procedure can return differe…
Microsoft Access has a limit of 255 columns in a single table; SQL Server allows tables with over 255 columns, but reading that data is not necessarily simple.  The final solution for this task involved creating a custom text parser and then reading…
Familiarize people with the process of utilizing SQL Server functions from within Microsoft Access. Microsoft Access is a very powerful client/server development tool. One of the SQL Server objects that you can interact with from within Microsoft Ac…
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.

876 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