Want to win a PS4? Go Premium and enter to win our High-Tech Treats giveaway. Enter to Win

x
?
Solved

table comparison in Acccess

Posted on 2011-02-10
5
Medium Priority
?
284 Views
Last Modified: 2012-05-11
I have 2 tables (A and B) with the same structure, what is the easiest way to obtain a list of combined record without double counting the row with the same record in a chosen field?
0
Comment
Question by:fitaliano
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 2
  • 2
5 Comments
 
LVL 31

Expert Comment

by:Helen Feddema
ID: 34864459
A union query should do it:


SELECT *
FROM tblContacts
UNION SELECT * FROM tblMoreContacts;

Open in new window

0
 

Author Comment

by:fitaliano
ID: 34864510
How do I ensure that Last Names are not double-counted?
0
 
LVL 77

Expert Comment

by:peter57r
ID: 34864825
Union will eliminate duplicates but the duplication is based on all selected fields.
If you want to base duplication just on one field then you will have to come up with some rules about how you decide which record to keep and which to remove.  You will probably then need a second process to get the final list.
0
 

Author Comment

by:fitaliano
ID: 34864913
Thanks Peter,

can you be more specific?

This is exactly what I would like to do:

I have [Address] and [Last Name] in both table A and B.

I want to obtain a list that combines both tables where the same [Last Name] in A and B is counted only once.  If there is a match between [Last Name] I want table A to win


0
 
LVL 77

Accepted Solution

by:
peter57r earned 2000 total points
ID: 34870324
In that case use your equivalent of...

Select * from tableA
Union
Select * from TableB as B where  not exists (Select Lastname from tableA where TableA.Lastname = B.Lastname)
0

Featured Post

Independent Software Vendors: We Want Your Opinion

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

Question has a verified solution.

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

If you need a simple but flexible process for maintaining an audit trail of who created, edited, or deleted data from a table, or multiple tables, and you can do all of your work from within a form, this simple Audit Log will work for you.
Code that checks the QuickBooks schema table for non-updateable fields and then disables those controls on a form so users don't try to update them.
In Microsoft Access, learn different ways of passing a string value within a string argument. Also learn what a “Type Mis-match” error is about.
Visualize your data even better in Access queries. Given a date and a value, this lesson shows how to compare that value with the previous value, calculate the difference, and display a circle if the value is the same, an up triangle if it increased…

618 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