Extracting rows that match preset letter

[bike5]

I made a page that will display links bases on the first letter in their sites name. Like clicking "A" will only display sites that have a name that starts with "A." When they add a site to my database, I made a colum with that letter, site_alpha . I know how to extract all the rows, and order them but how I do extract just rows that meet the first letter I will have in a link, like links.php?id=A thats what I will use to list the results.
All I have is

$Query = "SELECT site_alpha from $TableName";
$Result = mysql_db_query($DBName, $Query, $Link);
if($id=="A"){
while ($colum = mysql_fetch_array ($Result)) {

echo 'link goes here';

So how would I get it to only display results that match "A", colum named site_alpha.

Thanks a lot for your help.

[Anon]

Assuming: $id contains the letter

SELECT * FROM $TableName WHERE site_alpha='$id'

You can also skip the site_alpha column by creating a query:

SELECT * FROM $TableName WHERE title LIKE '$i%'

The % character functions as a wildcard.

[bike5]

Hey that worked. Thanks a lot.