&如何调&取父栏目及父栏目下的子栏目，以及子栏目下的子栏目？

后台界面的栏目分类：

栏目循环调取代码：

<?php 	
	$fnavSql=$empire->query("select * from `{$dbtbpre}enewsclass` where `bclassid`=1");
	while($fnav=$empire->fetch($fnavSql)){
?>
<fieldset class="fnav">
	<legend><a href="[!--news.url--]<?=$fnav[classpath]?>"><?=$fnav['classname']?></a></legend>
	<?php 
		$fnavSql2=$empire->query("select * from `{$dbtbpre}enewsclass`where `bclassid`='$fnav[classid]'");
		while($snav2=$empire->fetch($fnavSql2)){
	?>
	<fieldset class="snav2">
		<legend><a href="[!--news.url--]<?=$snav2['classpath']?>"><?=$snav2['classname']?></a></legend>
		<div class="snav3">
		<?php 
			$fnavSql3=$empire->query("select * from `{$dbtbpre}enewsclass`where `bclassid`='$snav2[classid]'");
			while($snav3=$empire->fetch($fnavSql3)){
		?>
			<a href="[!--news.url--]<?=$snav3['classpath']?>"><?=$snav3['classname']?></a>
		<?php
			}
		?>
		</div>
	</fieldset>
	<?php
		}
	?>
</fieldset>
<?php
	}
?>

css代码：

*{margin: 0;padding: 0;}
ul,li{list-style: none;}
a{display: block;line-height: 30px;text-decoration: none;}
.fnav{width: 350px;margin: 0 auto;}
legend{margin-left: .5em;padding: 0 .5em;}
.snav2{margin: 0 .5em;}
.snav3 a{text-indent: 1.5em;}

最终结果展示：