本文实例讲述了php+mysql查询实现无限下级分类树输出。分享给大家供大家参考，具体如下：
这里介绍的php结合mysql查询无限下级树输出，其实就是无限分类。给各位整理了几个php无限分类的例子.
树输出:
function get_array($user_id,$top=0){
global $mysql,$_G;
$sql = "select user_id as name from `{spreads_users}` where p1.spreads_userid="{$user_id}"";
$rows= $mysql->db_fetch_arrays($sql);
if($top==1){
$arr[0]["name"]=$user_id;
$arr[0]["children"]=array();
}
$top=$top+1;
foreach ($rows as $key=>$value)
{
$r = get_array($value["name"]); //调用函数，传入参数，继续查询下级
$arr[0]["children"][$key]["name"]= $value["username"]; //组合数组
if(is_array($r)){
$arr[0]["children"][$key]["children"]= $r[0]["children"];
}
$i++;
}
return $arr;
}
$list = get_array("1000",1); //调用函数1000是顶级ID
echo "var data=".json_encode($list);
这个是输出 Array 然后转让为 json
例子:
表结构:id字段为分类标识，name字段为分类名,father_id字段为所属父分类的id,path字段为分类路径,储存该分类祖先的集合,isdir判断是否是目录,1为是,0为否.
显示函数:
//$count为分类等级
sort_list($str,$fatherid,$count)
{
$rs = $this->sql->re_datas("select * from sort where father_id = fatherid");
$num = $this->sql->sql_numrows();
$i=0;
$n = 1;
while(isset($rs[$i]))
{
$name = "";
for($n = 1 ; $n < $count ; $n )
{
$name.="│ ";
}
if($i 1==$num)
{
$name.="└─".$rs[$i][name];
}
else
{
$name.="├─".$rs[$i][name];
}
if($rs[$i][isdir])
{
$str.="<span style="color:#CCCCCC">".$name."</span>";
}
else
{
$str.=$name";
}
$temp = $count 1;
$str = $this->sort_list($str,$rs[$i][id],$temp);
$i ;
}
return $str;
}
其中$this->sql对象为sql操作类对象,re_datas()函数返回查到的数组,sql_numrows()函数返回查询到的数目.
调用方法:
$sort_list = sort_list($sort_list,0,1);
例子:
表:category
id int 主键,自增
name varchar 分类名称
pid int 父类id，默认0
顶级分类的 pid 默认就是0了,当我们想取出某个分类的子分类树的时候,基本思路就是递归,当然,出于效率问题不建议每次递归都查询数据库,通常的做法是先讲所有分类取出来,保存到PHP数组里,再进行处理,最后还可以将结果缓存起来以提高下次请求的效率.
先来构建一个原始数组,这个直接从数据库中拉出来就行:
$categories = array(
array("id"=>1,"name"=>"电脑","pid"=>0),
array("id"=>2,"name"=>"手机","pid"=>0),
array("id"=>3,"name"=>"笔记本","pid"=>1),
array("id"=>4,"name"=>"台式机","pid"=>1),
array("id"=>5,"name"=>"智能机","pid"=>2),
array("id"=>6,"name"=>"功能机","pid"=>2),
array("id"=>7,"name"=>"超级本","pid"=>3),
array("id"=>8,"name"=>"游戏本","pid"=>3),
);
目标是将它转化为下面这种结构:
电脑 —笔记本 ——-超级本 ——-游戏本 —台式机 手机 —智能机 —功能机
用数组来表示的话,可以增加一个 children 键来存储它的子分类:
array(
//1对应id，方便直接读取
1 => array(
"id"=>1,
"name"=>"电脑",
"pid"=>0,
children=>array(
&array(
"id"=>3,
"name"=>"笔记本",
"pid"=>1,
"children"=>array(
//此处省略
)
),
&array(
"id"=>4,
"name"=>"台式机",
"pid"=>1,
"children"=>array(
//此处省略
)
),
)
),
//其他分类省略
)
处理过程:
$tree = array();
//第一步，将分类id作为数组key,并创建children单元
foreach($categories as $category){
$tree[$category["id"]] = $category;
$tree[$category["id"]]["children"] = array();
}
//第二部，利用引用，将每个分类添加到父类children数组中，这样一次遍历即可形成树形结构。
foreach ($tree as $k=>$item) {
if ($item["pid"] != 0) {
$tree[$item["pid"]]["children"][] = &$tree[$k];
}
}
print_r($tree);打印结果如下:
Array
(
[1] => Array
(
[id] => 1
[name] => 电脑
[pid] => 0
[children] => Array
(
[0] => Array
(
[id] => 3
[name] => 笔记本
[pid] => 1
[children] => Array
(
[0] => Array
(
[id] => 7
[name] => 超级本
[pid] => 3
[children] => Array
(
)
)
[1] => Array
(
[id] => 8
[name] => 游戏本
[pid] => 3
[children] => Array
(
)
)
)
)
[1] => Array
(
[id] => 4
[name] => 台式机
[pid] => 1
[children] => Array
(
)
)
)
)
[2] => Array
(
[id] => 2
[name] => 手机
[pid] => 0
[children] => Array
(
[0] => Array
(
[id] => 5
[name] => 智能机
[pid] => 2
[children] => Array
(
)
)
[1] => Array
(
[id] => 6
[name] => 功能机
[pid] => 2
[children] => Array
(
)
)
)
)
[3] => Array
(
[id] => 3
[name] => 笔记本
[pid] => 1
[children] => Array
(
[0] => Array
(
[id] => 7
[name] => 超级本
[pid] => 3
[children] => Array
(
)
)
[1] => Array
(
[id] => 8
[name] => 游戏本
[pid] => 3
[children] => Array
(
)
)
)
)
[4] => Array
(
[id] => 4
[name] => 台式机
[pid] => 1
[children] => Array
(
)
)
[5] => Array
(
[id] => 5
[name] => 智能机
[pid] => 2
[children] => Array
(
)
)
[6] => Array
(
[id] => 6
[name] => 功能机
[pid] => 2
[children] => Array
(
)
)
[7] => Array
(
[id] => 7
[name] => 超级本
[pid] => 3
[children] => Array
(
)
)
[8] => Array
(
[id] => 8
[name] => 游戏本
[pid] => 3
[children] => Array
(
)
)
)
优点:关系清楚,修改上下级关系简单.
缺点:使用PHP处理,如果分类数量庞大,效率也会降低.
更多关于PHP相关内容感兴趣的读者可查看本站专题：《php+mysql数据库操作入门教程》、《PHP基本语法入门教程》、《PHP运算与运算符用法总结》、《php面向对象程序设计入门教程》、《PHP网络编程技巧总结》、《PHP数组(Array)操作技巧大全》、《php字符串(string)用法总结》及《php常见数据库操作技巧汇总》
希望本文所述对大家PHP程序设计有所帮助。
