?
Solved

ADo select double numbers

Posted on 2009-04-03
9
Medium Priority
?
199 Views
Last Modified: 2013-11-23
I have a table with
Name, Number, Extention, Group
Eacht name has 2 extentions but the number is the same.

Now I need to selct one name from each Number. I am still getting double records as result.
I have
Jack, 3, 124, Marketing and I have Jack 1, 3, 123, Marketing
I need to select only one of these
My code is 
     SQL.Add('Select  distinct M_number, M_name, M_Extention, Group');
     SQL.Add('From Employees);
     SQL.Add('Where (Group = '+QuotedStr(Group)+')');
 
 
What is wrong in this?

Open in new window

0
Comment
Question by:Nayel
[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
  • 5
  • 4
9 Comments
 
LVL 38

Expert Comment

by:Geert Gruwez
ID: 24057849
you are selecting multiple different ones with distinct not 1

and use parameters for performance, allways better !
and Group is a reserved word (bettter to use other column name)





as i dunno what database ... for oracle:
SELECT M_number, M_name, M_Extention, Group
FROM (SELECT M_number, M_name, M_Extention, Group, RANK() OVER (PARTITION BY M_Number ORDER BY M_Number) X
            WHERE GROUP = :AGRoup)
WHERE X = 1

Open in new window

0
 

Author Comment

by:Nayel
ID: 24057862
I am using Access
0
 
LVL 38

Expert Comment

by:Geert Gruwez
ID: 24057904
that's not a database ... it's a flat file :)

SELECT E.*
FROM Employees E,
  (SELECT M_Number, Min(M_Name) XName FROM Employees Group By M_Number) X
WHERE E.M_Number = X.M_Number
  AND E.M_Name = X.XName

0
Technology Partners: 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!

 

Author Comment

by:Nayel
ID: 24057920
No no.. I am using Delphi which is connected to Access. And the query should be written in an ADOQUERY
0
 
LVL 38

Expert Comment

by:Geert Gruwez
ID: 24057950
just kidding
var AdoQuery: TAdoQuery;
begin
  AdoQuery.SQL.Text := 
    'SELECT E.* FROM Employees E,           '+
    '  (SELECT M_Number, Min(M_Name) XName  '+ 
    '   FROM Employees Group By M_Number) X '+
    'WHERE E.M_Number = X.M_Number          '+
    '  AND E.M_Name = X.XName               '+
    '  AND E.Group = :GROUP                 ';
  AdoQuery.Parameters.ParamByName('GROUP').Value := Group;
  AdoQuery.Open;

Open in new window

0
 

Author Comment

by:Nayel
ID: 24058035
Getting a fault.
0
 
LVL 38

Expert Comment

by:Geert Gruwez
ID: 24058039
and that would be ?

i tried to smell what it was, but i have a small cold ...
0
 

Author Comment

by:Nayel
ID: 24058073
A syntaxerror in expression Min(M_Name) XName
0
 
LVL 38

Accepted Solution

by:
Geert Gruwez earned 200 total points
ID: 24058080
I'm not supergood in access,
I try to stay away from it,
but try this:
var AdoQuery: TAdoQuery;
begin
  AdoQuery.SQL.Text := 
    'SELECT E.* FROM Employees E,              '+
    '  (SELECT M_Number, Min(M_Name) AS XName  '+ 
    '   FROM Employees Group By M_Number) AS X '+
    'WHERE E.M_Number = X.M_Number             '+
    '  AND E.M_Name = X.XName                  '+
    '  AND E.Group = :GROUP                    ';
  AdoQuery.Parameters.ParamByName('GROUP').Value := Group;
  AdoQuery.Open;

Open in new window

0

Featured Post

Free Tool: SSL Checker

Scans your site and returns information about your SSL implementation and certificate. Helpful for debugging and validating your SSL configuration.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

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

Creating an auto free TStringList The TStringList is a basic and frequently used object in Delphi. On many occasions, you may want to create a temporary list, process some items in the list and be done with the list. In such cases, you have to…
Introduction Raise your hands if you were as upset with FireMonkey as I was when I discovered that there was no TListview.  I use TListView in almost all of my applications I've written, and I was not going to compromise by resorting to TStringGrid…
NetCrunch network monitor is a highly extensive platform for network monitoring and alert generation. In this video you'll see a live demo of NetCrunch with most notable features explained in a walk-through manner. You'll also get to know the philos…
In this video, Percona Solution Engineer Dimitri Vanoverbeke discusses why you want to use at least three nodes in a database cluster. To discuss how Percona Consulting can help with your design and architecture needs for your database and infras…
Suggested Courses

764 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