Somar dados da Tabela String

    with Query1 do begin
       Close;
       SQL.Text := ´select Sum(cast(Campo1 as numeric(10,2))) as Soma1, Sum(cast(Campo2 as numeric(10,2))) as Soma2 from dbTabela.db´;
       Open;
   end;

Var S: String;
    VALOR : double;
begin

VALOR := 0;
ProgressBar1.Max      := TABELA.RecordCount;
ProgressBar1.Position := 0;
ProgressBar1.Step     := 1;

While not TABELA.EOF do begin
     S := TABELA.FieldByName(´Campo1´).asString;

     //Remove espaços
     While pos(´ ´, S) > 0 do
         Delete(S, Pos(´ ´,S), 1);

     //Remove ponto de milhar
     While pos(´.´, S) > 0 do
         Delete(S, Pos(´.´,S), 1);

     //Substitui virgula por ponto decimal
     While pos(´,´, S) > 0 do
         S[Pos(´,´,S)] := ´.´;

     //Testa se S é ponto flutuante
     try
        StrToFloat( S );
     Except On EConvertError do begin
        ShowMessage(´Erro convertendo "´ + S + ´"´ );
        exit;
        end;
     end;

     //Acumula Valor
     VALOR := VALOR + StrToFloat( S );

     //Progresso (pra distrair o usuário, rs)
     ProgreessBar1.Stepit;

     //Avança Tabela
     TABELA.Next;

end;