Questions about PHP queries in MySQL?

PHP query in MySQL problem??
I want to query the data for the corresponding value based on a value. Example: Know the value of user and then display the PWD value. The code I tested in Phpamdin was:

$sql = ' SELECT pwd '
        . ' From ' AppData '
        . ' WHERE user = \[email protected]\ ' LIMIT 0, 30 ';

But adding the PHP file inside the execution is always unsuccessful.

Here is my code, how to modify it?

 
     Include_once "logindatabase.php";
    $cmd = mysql_query (SELECT * from AppData WHERE user [email protected]);
    $rec = Mysql_fetch_array ($cmd);
    echo $rec [PWD];
?>

Thank you, everyone.
------Solution--------------------
Include_once "logindatabase.php";
$cmd = mysql_query (' SELECT * from AppData WHERE user= ' [email protected] ');
$rec = Mysql_fetch_array ($cmd);
while ($rec = Mysql_fetch_array ($cmd))
echo $rec [' Pwd '];
?>

