Order rows and display order number

Question

I already have a query which results like this

+-----------+------------+---------------+--------+
| DetailsNo |  SaleDate  | Country       | Value  |
+-----------+------------+---------------+--------+
|       277 | 2012-02-10 | PHI           |     42 |
|       279 | 2012-02-10 | PHI           |     10 |
|       280 | 2012-02-10 | USA           |     30 |
|       281 | 2012-02-10 | USA           |     25 |
|       282 | 2012-02-10 | FRA           |     65 |
|       283 | 2012-02-10 | FRA           |     36 |
|       284 | 2012-02-10 | GER           |     47 |
+-----------+------------+---------------+--------+

What i need is to add another column and display a sort of order number like the following :

+-----------+------------+---------------+--------+--------+
| DetailsNo |  SaleDate  | Country       | Value  | Order  |
+-----------+------------+---------------+--------+--------+
|       277 | 2012-02-10 | PHI           |     42 |      1 |
|       279 | 2012-02-10 | PHI           |     10 |      2 |
|       280 | 2012-02-10 | USA           |     30 |      1 |
|       281 | 2012-02-10 | USA           |     25 |      2 |
|       282 | 2012-02-10 | FRA           |     65 |      1 |
|       283 | 2012-02-10 | FRA           |     36 |      2 |
|       284 | 2012-02-10 | GER           |     47 |      1 |
+-----------+------------+---------------+--------+--------+

Is this possible?

Answer 1

You can use variables for this:

SELECT DetailsNo, SaleDate, Country, Value,
       @rn := IF(@c = Country, @rn + 1,
                 IF(@c := Country, 1, 1)) AS 'Order'
FROM mytable
CROSS JOIN (SELECT @rn := 0, @c := '') AS vars
ORDER BY Country, DetailsNo

Demo here