用动态变量更新pdo

Ok so i am trying to use a variable i set in side pdo update i echo out all of the variable which are in the pdo update and all are set but the update does not seem to work.... I think im just missing single / double quotes

$myName = mysql_real_escape_string($_POST['myName']);
$mydropdown = mysql_real_escape_string($_POST['mydropdown']);





    if ($mydropdown == '1') {$tablename = "poke1";}
if ($mydropdown == '2') {$tablename = "poke2";}
if ($mydropdown == '3') {$tablename = "poke3";}
if ($mydropdown == '4') {$tablename = "poke4";}
if ($mydropdown == '5') {$tablename = "poke5";}
if ($mydropdown == '6') {$tablename = "poke6";}


echo $tablename;


$sqll = "UPDATE users SET '$tablename'=? WHERE username=?";
    $q = $db->prepare($sqll);
    $q->execute(array($myName,$_SESSION['username']));

Also i have echoed out the tablename and the myName both are vaild and set to the correct thing

Use backticks ` instead of single quotes:

$sqll = "UPDATE users SET `$tablename`=? WHERE username=?"; 

Also, are you sure its SET $tablename, or does $tablename hold column names?

A little bit optimized code:

$myName = mysql_real_escape_string($_POST[`myName`]);

$tablename = null;

for($i = 1; $i < 7; $i++){

    if($_POST[`mydropdown`] == $i) $tablename = `poke`.$i;
}

if(!is_null($tablename)){

    echo $tablename;

    $q = $db->prepare("UPDATE users SET `$tablename`=:tablename WHERE username=:username");
    $q->bindParam(`:tablename`, $myName);
    $q->bindParam(`:username`, $username);
    $q->execute();
}