mysql_real_escape_string and htmlspecialchars while matching

[vinpkl]

hi all

Do we use mysql_real_escape_string and htmlspecialchars while matching the values from database

<?
$user_id = mysql_real_escape_string($_POST['user_id']);

if($user_id = $row['user_id']
{
    /* do something */
}
?>

or

<?
$user_id = mysql_real_escape_string($_POST['user_id']);

if($user_id == mysql_real_escape_string($row['user_id'])
{
    /* do something */
}
?>

or

<?
$user_id = mysql_real_escape_string($_POST['user_id']);

if($user_id == htmlspecialchars($row['user_id'])
{
    /* do something */
}
?>

vineet