Using AES_DECRYPT, results: Null

[Enlightened]

Hello, im trying to use AES_DECRYPT with a column, And it returns NULL, I do

know that field isnt NULL, Ive tried mysql's reference as well as a few others, Can

anyone notice what i am doing wrong?

    $query = "SELECT @moo:=moo FROM table_salt;";

$query2 = "SELECT AES_DECRYPT('d_ssn', @moo) as ssn FROM contact";

$result = mysql_query($query);

$result2 = mysql_query($query2);

if($result && $result2)

{....