Sorting timestamps

[Anon]

I have a sales table and every time a sale is made a timestamp is also saved.

I wish to output a graph which show sales hour by hour, I mean something like:

00.00 1 sale
01.00 2 sales

02.00 0 sales

-

23.00 4 sales.

I plan to use the date function, and put the number of sales in an array with 24 elements, but how do I easiest sort my timestamps without a lot of if >,<,= loops etc....?

[crimaniak]

Like this:

Select count(*) as sales, LEFT(timestamp,10) as ts from sales_table Group by LEFT(timestamp,10) order by ts

(year, month, day, hour, but no minutes or seconds)