Someone

$data = $xml->xpath('//BUY_DATA_BROCHURE');

$valuesString = '';
foreach ($data as $key => $xmlData) {

            $valuesString .= '(';
    
            foreach($xmlData as $field => $value) {
                
                $valuesString .= $value. ',';
            }
            
            $valuesString .= ')';
    
}

$SQL = "INSERT INTO TABLE {$tableName} VALUES {$valuesString};";