procedure TForm2.Button1Click(Sender: TObject);
var
desde, hasta: string ;
begin
with Query1 do begin
Active := False;
with SQL do begin
Clear;
desde := txtdesde.text;
hasta := txthasta.text;
QUERY1.SQL.ADD('SELECT employee.EmpNo, LastName, FirstName,');
QUERY1.SQL.ADD('SUM(ItemsTotal) AS Ventas');
QUERY1.SQL.ADD('FROM employee LEFT JOIN orders');
QUERY1.SQL.ADD('ON employee.EmpNo = orders.EmpNo');
QUERY1.SQL.ADD('WHERE SaleDate BETWEEN "' + desde + '" AND "' +
hasta + '"');
QUERY1.SQL.ADD('GROUP BY employee.EmpNo, LastName, FirstName');
end;
Active := True;
end;