ช่วยดูโค้ดให้หน่อยครับ ผมเขียนแล้วทำไมมัน echo ไม่ขึ้นตัวเลขเลย

<?php
$selectcount = "SELECT count(loggedin) FROM 'accounts' WHERE loggedin = 2";
$count_online = mysql_query($selectcount);
echo $count_online;
?>

$selectcount="select count(loggedin) as count from accounts where loggedin = '2' ";
$count_online = mysql_query($selectcount);
echo "$count_online[count]";

<?php
$selectcount = "SELECT count(loggedin) FROM 'accounts' WHERE loggedin = 2";
$count_online = mysql_query($selectcount);
echo $count_online['count(loggedin)'];
?>