var code:string;
begin
With dm.ADOQuery1 do begin
Close;
SQL.Clear;
SQL.Add('SELECT * FROM CENTROSEDUC');
If COMBOBOX1.Text <> 'Todos los Distritos' then
begin
code := copy(combobox1.text, 1,2) + copy(combobox1.text, 6,2);
sql.Add(' where Distrito ='+Quotedstr(code));
end;
Open;
end;
end;