PHP Bei Suchfunktion erschein Fehlermeldung

[borklaser]

Ich habe eine Tabelle gemacht mit Auf & Absteigens sortierung. Die Tabellenzeilen werden aus der MySQL Datenbank geladen. Über der Tabelle habe ich eine Suchfunktion, die de Tabelle durchsucht und die Ergebnisse auch in der gleichen Tabelle anzeigt. Allergins kommt eine Fehlermeldung wenn ich auf Suchen klicke:

You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'WHERE ppvname = OR datum = OR art = OR buyrate = OR matches =' at line 1

Kann mir jemand sagen was ich genau machen muss damit die Melldung weggeht und die Suchfunktion funktionier? Habe echt keine Ahnung was ich machen soll. Danke, da der Code...

<?php



include "connection.php";

if ( isset ( $_GET['order_var'] ) )
{
        $order_var = $_GET['order_var'];

        switch ( $order_var )
        {
                case 'ppvname_asc':
                        $order_var = "ppvname ASC";
                        break;
                case 'ppvname_dsc':
                        $order_var = "ppvname DESC";
                        break;
                case 'datum_asc':
                        $order_var = "datum ASC";
                        break;
                case 'datum_dsc':
                        $order_var = "datum DESC";
                        break;
                case 'art_asc':
                        $order_var = "art ASC";
                        break;
                case 'art_dsc':
                        $order_var = "art DESC";
                        break;
                case 'buyrate_asc':
                        $order_var = "buyrate ASC";
                        break;
                case 'buyrate_dsc':
                        $order_var = "buyrate DESC";
                        break;

                case 'matches_asc':
                        $order_var = "matches ASC";
                        break;
                case 'matches_dsc':
                        $order_var = "matches DESC";
                        break;
        }
}
else
{
        $order_var = "ppvname ASC";
}




$sql = "SELECT * FROM PPVs ORDER BY $order_var ";

if (isset($_POST['search'])) {
$search_term = mysql_real_escape_string($_POST['search_box']);
    $sql .= "WHERE ppvname =".$search_term ;
    $sql .= " OR datum   = ".$search_term ;
    $sql .= " OR art   = ".$search_term ;
    $sql .= " OR buyrate   = ".$search_term ;
    $sql .= " OR matches   = ".$search_term ;

}


$query = mysql_query($sql) or die(mysql_error());


$ppvname_var = "ppvname_asc";
$datum_var = "datum_asc";
$art_var = "art_asc";
$buyrate_var = "buyrate_asc";
$matches_var = "matches_asc";

if ( $order_var == "ppvname ASC" )
{
        $ppvname_var = "ppvname_dsc";
}
else if ( $order_var == "ppvname DESC" )
{
        $ppvname_var = "ppvname_asc";
}

if ( $order_var == "datum ASC" )
{
        $datum_var = "datum_dsc";
}
else if ( $order_var == "datum DESC" )
{
        $datum_var = "datum_asc";
}

if ( $order_var == "art ASC" )
{
        $art_var = "art_dsc";
}
else if ( $order_var == "art DESC" )
{
        $art_var = "art_asc";
}

if ( $order_var == "buyrate ASC" )
{
        $buyrate_var = "buyrate_dsc";
}
else if ( $order_var == "buyrate DESC" )
{
        $buyrate_var = "buyrate_asc";
}

if ( $order_var == "matches ASC" )
{
        $matches_var = "matches_dsc";
}
else if ( $order_var == "matches DESC" )
{
        $matches_var = "matches_asc";
}




?>
<form name="search_form" method="POST" action="display_data.php">
Search: <input type="text" name="search_box" value="" />
<input type="submit" name="search" value="Suchen"/>

</form>
<table width="70%" cellpadding="5" cellspacing="5">
<tr>

<td>Veranstaltung <a href="display_data.php?order_var=ppvname_asc">&#9660;</a> <a href="display_data.php?order_var=ppvname_dsc">&#9650;</a></td>
<td>Datum <a href="display_data.php?order_var=datum_asc">&#9660;</a> <a href="display_data.php?order_var=datum_dsc">&#9650;</a></td>
<td>Art <a href="display_data.php?order_var=art_asc">&#9660;</a> <a href="display_data.php?order_var=art_dsc">&#9650;</a></td>
<td>Buyrate <a href="display_data.php?order_var=buyrate_asc">&#9660;</a> <a href="display_data.php?order_var=buyrate_dsc">&#9650;</a></td>
<td>Matches <a href="display_data.php?order_var=matches_asc">&#9660;</a> <a href="display_data.php?order_var=matches_dsc">&#9650;</a></td>

</tr>

<?php while ($row = mysql_fetch_array($query)) { ?>

<tr>

<td><?php echo $row['ppvname']; ?></td>
<td><?php echo $row['datum']; ?></td>
<td><?php echo $row['art']; ?></td>
<td><?php echo $row['buyrate']; ?></td>
<td><?php echo $row['matches']; ?></td>

</tr>


<?php } ?>

</table><?php





?>