How do you sort php and sql arrays?

How can I sort this array by city or by id i开发者_如何学Pythonn descending order?

if ($num > 0 ) {
$i=0;
while ($i < $num) {
$city = mysql_result($result,$i,"city");
$state = mysql_result($result,$i,"state");
$id = mysql_result($result,$i,"id");

echo "$city";
echo "$state";

++$i; } } else { echo "No results."; } ?>

You didn't include your SQL code in the above post, but that is the part of the code where you are supposed to add the ORDER BY sorting function as follows:

SELECT * FROM address_table ORDER BY city desc

you can also use "LIMIT" for one city: SELECT * FROM address_table ORDER BY city desc LIMIT 0,1 - returns 1 row