Firebird, Delphi - Need help in an efficient way of updating a table

The thing with the Select function is that I want to edit the 6 records(players) with the highest Def skill set. The other records are not to be updated(there are about 30 records per team, only 6 are to be edited).

I am only using this in my program in memory - need to do the calculation to get the team skill, so I need to do a fast calculation.

Forgot to ask what it means with "calculated fields" ? How to use and take advantage of this?

a calculated field is a field you add to the dataset
put a query on a form
right click and click edit fields
then you can add fields
you set the type to calculated

then assign the oncalculate event handler
this gets called for each record on loading the data, and you can set the value of your fields to what you want

procedure TForm1.Query1OnCalculate(Dataset: TDataset);
begin
  DataSet.FieldByName('TOTAL').AsFloat := Dataset.FieldByName('QUANTITY').AsFloat * DataSet.FieldByName('PRICE').AsFloat;
end;

Sounds good, but didn't get it to work with Zeos? Any good tutorial link for calc?

The main problem I have though is the following:

I have a query that returns, say 5 results and I would like the Off field (number 1-20) from those 5 results to be added to count_off.caption.

with Spelare do
      begin
      Close;
      SQL.Clear;
      SQL.text := 'select first 5 * from spelare where klubb = ''Tomteland'' and Pos = ''F'' order by Off DESC';
      Open;
end;
 
//Adding this, which is probably not that efficient, will only give me the number of the first result's Off field (not the total amount from the returned results).
 
count_off.caption.caption := inttostr(strtoint( count_off.caption) + strtoint(Spelare['Off']));
 
//

                                              

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"//Adding this, which is probably not that efficient, will only give me the number of the first result's Off field (not the total amount from the returned results)."

Okay, well then why don't you cycle/iterate through your dataset and add up the off field that way?

var
 i : integer;

i := 0;

MyDataset.First;

While MyDataset.eof = false do

begin

 i := i + MyDataSet.Fieldbyname('Off').asInteger;
 MyDataset.Next;

end;

Thanks, that did the trick; however, my final question before I close and accept it as a solution is how I, at the same time, can update the results?

with Spelare do
      begin
      Close;
      SQL.Clear;
      SQL.text := 'select first 3 skip 3 * from spelare where klubb = ''+nuvklubb.caption+''' and Pos = ''B'' order by Def DESC';
      Open;
end;
i := 0;
Spelare.First;
While Spelare.eof = false do
begin
 i := Spelare.Fieldbyname('Def').asInteger;
 Spelare.sql.text := 'update spelare set platsar = ''2''';
 Spelare.Next;
end;

                                              

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Hey I see an error in your code that I have repeated above. You say:
  i := Spelare.Fieldbyname('Def').asInteger
that should be:
 i := i +  Spelare.Fieldbyname('Def').asInteger;
otherwise i will not count.

Thanks for all your information and tips, very useful.

Sorry if I've said different things, its because I haven't found the best solution for the query yet. Unfortunately, I do not have any ID for the table.

LineUp has nothing to do with the DB, its just a label.

6 records will be chosen.

First 2 should have its 'Def' attributes added to Line1Def, and their 'Platsar' should be set to '1'.
#3 and #4 should have its 'Def' attribute added to Line2Def, and their 'Platsar' should be set to '2'.
#5 and #6 should have its 'Def' attribute added to Line3Def and their 'Platsar' should be set to '3'.

It needs to be a fast procedure since it will be used a lot in updating lineups for the teams.

//By adding this I will pull the first 2 results of the 6 (seemed like an easy method, but requires a lot of coding (copy/change/paste) and will probably be a little bit slow.
 
with Spelare
do
      begin
      Close;
      SQL.Clear;
      SQL.text := 'select first 2 * from spelare where klubb = ''+nuvklubb.caption+''' and Pos = ''B'' order by Def DESC';
      Open;
end;
i := 0;
Spelare.First;
While Spelare.eof = false do
begin
 i := i + Spelare.Fieldbyname('Def').asInteger;
 Spelare.Next;
end;
Line1Def.Caption := inttostr(i);
 
//Doing the following will give the error "Expression expected but '>' found. Looked like a good solution otherwise though since it will be a lot less coding to go through. But do I have to go with Edit/Post? It's a bit slower, isn't it?
 
  While Spelare.eof = false do
  begin
   if (Spelare.RecNo => 0) and (Spelare.RecNo <= 1) then
   begin

                                              

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sorry change => to >=
i forget that it likes to say "..is greater than or equal to" but doesn't like "is equal to or greater than".

I'm also slightly confused about which are your datasets and which are your table names. I suspect you have a TZTable or TZQuery called "Spealer" and also a table in your database called "Spealer". It's probably my fault, I should read through all of this carefully to understand 100%