<?php

$keywords       = 'in mysql db suchen';
$association    = "\n".' AND ';
$keywords       = explode(' ', $keywords);

$query = array(); 

foreach ($keywords as $keyword) { 
    $query[] = "(   `name_des_ersten_felds`     LIKE '%".$keyword."%'
                OR  `name_des_zweiten_felds`    LIKE '%".$keyword."%'
                OR  `name_des_dritten_felds`    LIKE '%".$keyword."%'
                OR  `und_so_weiter`             LIKE '%".$keyword."%')
                ";
} 

$query = implode($association, $query); 

$sql = "
    SELECT  *
    FROM    `name_der_tabelle`
    WHERE   ".$query."
;"
$res = mysql_query($sql);

if (!$res) {
    /**
     * Diese Zeilen das SQL-Statement in recht lesbarer Form aus.
     */
    print '<pre>';
    print $sql;
    print '</pre>';
    /**
     * E_USER_ERROR führt zu Abbruch des Scripts.
     * E_USER_NOTICE und E_USER_WARNING, lassen das Script weiterlaufen
     */
    trigger_error('Datenbankanfrage schlug fehl: '.mysql_error(), E_USER_ERROR);
} else {
    /**
     * Hier die Routi(e)nen zum Auslesen des RecordSets einfügen. 
     */
}

?>

 SELECT * FROM literatur WHERE '.( `f200` LIKE '%Adv%' 
OR `f300` LIKE '%Adv%' 
OR `f720` LIKE '%Adv%' 
OR `f800` LIKE '%Adv%') 

 OR ( `f200` LIKE '%Weih%' 
OR `f300` LIKE '%Weih%' 
OR `f720` LIKE '%Weih%' 
OR `f800` LIKE '%Weih%') 

 OR ( `f200` LIKE '%Ost%' 
OR `f300` LIKE '%Ost%' 
OR `f720` LIKE '%Ost%' 
OR `f800` LIKE '%Ost%') 

 OR ( `f200` LIKE '%Pfin%' 
OR `f300` LIKE '%Pfin%' 
OR `f720` LIKE '%Pfin%' 
OR `f800` LIKE '%Pfin%') 

 OR ( `f200` LIKE '%Kar%' 
OR `f300` LIKE '%Kar%' 
OR `f720` LIKE '%Kar%' 
OR `f800` LIKE '%Kar%') 
.'
Unbekanntes Tabellenfeld 'Adv' in where clause.
SELECT * FROM literatur WHERE '.( `f200` LIKE '%Adv%' OR `f300` LIKE '%Adv%' OR `f720` LIKE '%Adv%' OR `f800` LIKE '%Adv%') OR ( `f200` LIKE '%Weih%' OR `f300` LIKE '%Weih%' OR `f720` LIKE '%Weih%' OR `f800` LIKE '%Weih%') OR ( `f200` LIKE '%Ost%' OR `f300` LIKE '%Ost%' OR `f720` LIKE '%Ost%' OR `f800` LIKE '%Ost%') OR ( `f200` LIKE '%Pfin%' OR `f300` LIKE '%Pfin%' OR `f720` LIKE '%Pfin%' OR `f800` LIKE '%Pfin%') OR ( `f200` LIKE '%Kar%' OR `f300` LIKE '%Kar%' OR `f720` LIKE '%Kar%' OR `f800` LIKE '%Kar%') .'