Have some problem to insert data in Mysql table. I have this code:

<?php
$city_menu = $_POST["city_menu"];
?>

<FORM Method="post" ACTION="<?php echo $PHP_SELF;?>">

<select name="city_menu">
<option value="Jr.High">Jr.High</option>
<option value="HighSchool">HighSchool</option>
</select>

</form>

<?php
$con = mysql_connect("mysql-lotus.x10hosting.com", "md7dani2_myuser", "xxxx");

if (mysql_select_db("md7dani2_haveroom", $con))
{
echo "Database open";
}
else
{
echo "Error open database: " . mysql_error();
}

mysql_query("INSERT INTO Spec (city) VALUES ($city_menu)"); <-- this doesn't work, how do I save variable '$city_menu' in table Spec??

mysql_close($con);
?>

have looked it up, should be:
$sql = "INSERT INTO Spec (city) VALUES('$city_menu')";

thanks.