Calculate using a field in current & prev record

would this work for you?

function Difference(Direction: string): integer;
var
  Current: integer;
begin
  Current := table.fieldByname('calculated').AsInteger; // get current value;

  if Direction = 'Next' then
  begin    
    table.Next;
    result := table.fieldbyname('calculated').AsInteger - current;
    table.previous;
  end
  else if Direction = 'Previous' then
  begin
    table.previous;
    result := current - table.fieldbyname('calculated').AsInteger;
    table.next;
  end
  else
    result := 0;
end;

assuming your table is called table etc.

Hope that helps,

Dave.

Adjusted points from 40 to 100

Edited text of question.

What database server are you using?

Alex

Hi Simonet,

No server, just a small paradox 7 table, stand alone pc.

Is my question clear ? It almost seems as if I wrote it a bit confusing.

I have a field which stores a value. All I would like to do is create an extra field or whatever to display the movements of the difference between this field's values between records It should display this "movement" field in a dbgrid preferably.

I am quite new to delphi / Paradox etc.
If you know FileExpress for example, you could enter a function which will calculate the movement between fields in different records by accessing the next or previous records without moving the focus to them i.e.



field_z := field_3 - field_3(prev)

Can you possibly help me to an answer.

Cheers

Comment accepted as answer

Thanks Ivan,

I can use it, it works ok.

cheers - Surv

You well come.

Ivan