Remove duplicate entries, select data

[Anon]

Hi
I have a code that populates a drop down box with data from a mysql table. What i want to do is not to list the same piece of data twice. Here is my example

Im selected city from the tableinclude

include ("customer_table.inc");
$connection = @mysql_connect("", "", "") or die("Couldn't connect.");

$db = @mysql_select_db($db_name, $connection)or die("Couldn't select database.");

$sql = "Select city from $table_name ";

$result = @($sql,$connection)or die("Couldn't execute query.");

while ($row = mysql_fetch_array($result)){
$city = $row['city'];

$option_block3 .= "<option value = \"$city\">$city</option>";

So, if there are two or more occurences of the same city, i only want one to appear in the drop down option box.

Thanks for any help

}

[amcgrath]

$sql = "Select DISTINCT city from $table_name ";