为何smarty循环fetch的话，每次内容都一样

foreach ( $category as $c ) {
	$products = $util->getArrayByQueryString ( "select * from product_detail where sid=$c[id]" );
	$smarty->assign ( "html_title", $c [name] . '：所有子类产品' );
	$smarty->assign ( "products", $products );
//	foreach ( $products as $p ) {
//		echo $p [id] . $p [name] . '
';
//	}
	$content = $smarty->fetch ( "products.tpl" );
	$file_name = './products/' . $c [id] . '.html';
	//html生成
	create_html ( $file_name, $content );
}