How to concatenate strings from fields of different records in a Paradox database

Posted on 2004-08-18
Last Modified: 2010-04-05
Hi, can anyone help me on this:

I have a paradox database that f.i. contains a field ''Unit" ( string)

What I want to do is to concatenate the value of this field , I'l get more specific with an example

record 1: Unit = "Mario"
record 2: Unit = "Peter"
record 3: Unit = "Marc"

Result --> "Mario / Peter / Marc" --> string

Can this be done by using SQL ?

Question by:marioway
LVL 27

Accepted Solution

kretzschmar earned 500 total points
ID: 11835349
use a tquery

place a statement like

select unit from yourtablename

adjust the other propertys of the query (ie. databasename->your alias)

then use a buttonclickevent like

var result : String;
  result := '';;
  while not query1.eof do
    result := result * query1.fieldByName('unit').AsString + ' / ';
  //remove last ' / '

just from head -> typos possible

hope this helps

meikl ;-)
LVL 14

Expert Comment

by:Pierre Cornelius
ID: 11835635
I doubt you can do it with the way your database is set up. You can concatenate strings from different fields in a single record (e.g. SELECT Field1||Field2 FROM SomeTable) but as far as I know, you can't do it on various records.

If you only want it for a few records, there is a bit of a long winded approach to your problem. Assuming your unique record identifier is IDNumber, and you want to concatenate the records for IDNumbers "123", "456" and "789" do the following:
1.) save the following as a text file in your database directory:
     SELECT IDNumber, Unit FROM YourTable WHERE IDNumber = 123 /*or "123" if it is a text field*/
    -> Call it Source1.sql for purposes of this example

2.) save the following as a text file in your database directory:
     SELECT IDNumber, Unit FROM YourTable WHERE IDNumber = 456
    -> Call it Source2.sql for purposes of this example

3.) save the following as a text file in your database directory:
     SELECT Unit FROM YourTable WHERE IDNumber = 789
    -> Call it Source3.sql for purposes of this example

4.) Execute the following query:
    SELECT s1.Unit||"/"||s2.Unit||"/"||s3.Unit
    FROM "c:\YourDBPath\source1.sql" s1,
             "c:\YourDBPath\source2.sql" s2,
             "c:\YourDBPath\source3.sql" s3

E.G. Using the DBDemos table Industry I have done this using the following:
- SELECT * FROM Industry WHERE IND_CODE = 3579 saved as Source1.sql
   in "C:\Program Files\Common Files\Borland Shared\Data\"
- SELECT * FROM Industry WHERE IND_CODE = 3710 saved as Source2.sql
   in "C:\Program Files\Common Files\Borland Shared\Data\"
- SELECT * FROM Industry WHERE IND_CODE = 7000 saved as Source3.sql
   in "C:\Program Files\Common Files\Borland Shared\Data\"

- Execute this query:
  SELECT s1.IND_NAME||"/"||s2.IND_NAME||"/"||s3.IND_NAME AS UnitCombined
  "C:\Program Files\Common Files\Borland Shared\Data\Source1.sql" s1,
  "C:\Program Files\Common Files\Borland Shared\Data\Source2.sql" s2,
  "C:\Program Files\Common Files\Borland Shared\Data\Source3.sql" s3
- Results:

As I said, this is a rather longwinded approach. Depending on your needs and on how many records you need to concatenate, you might find something like the following more useful:

function ConcatenateFields(DataSet: TDataset; ConcatField: string): string;
  result:= '';
  While not DataSet.Eof do
    result:= result+DataSet.FieldByName(ConcatField).AsString+'/';
  if result <> '' then result:= copy(result,1,Length(result)-1); //get rid of the last slash

Hope this helps.

Kind regards
Pierre Cornelius

Author Comment

ID: 11839559
Hello, Kretchzmar, I changed th code a bit, now it looks like this and it works fine

procedure TForm1.Button1Click(Sender: TObject);
var i: integer ;
    i1, i2, i3 : string;
query1.Close;   (Select Eenheidsmaat from artikel.db)
i1:= Query1Eenheidsmaat.Value;   (or Unit in the question)
for i:= 0 to query1.RecordCount - 1 do
  i3:= i1;
  i2:= '/' + query1Eenheidsmaat.Value;
  i1:= i3 + i2;
Label1.Caption:= i3;

thx alot


Featured Post

Is Your Active Directory as Secure as You Think?

More than 75% of all records are compromised because of the loss or theft of a privileged credential. Experts have been exploring Active Directory infrastructure to identify key threats and establish best practices for keeping data safe. Attend this month’s webinar to learn more.

Question has a verified solution.

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

Suggested Solutions

A lot of questions regard threads in Delphi.   One of the more specific questions is how to show progress of the thread.   Updating a progressbar from inside a thread is a mistake. A solution to this would be to send a synchronized message to the…
Objective: - This article will help user in how to convert their numeric value become words. How to use 1. You can copy this code in your Unit as function 2. than you can perform your function by type this code The Code   (CODE) The Im…
Video by: Mark
This lesson goes over how to construct ordered and unordered lists and how to create hyperlinks.
Hi friends,  in this video  I'll show you how new windows 10 user can learn the using of windows 10. Thank you.

867 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