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示例php+mysql查询实现无限下级分类树输出

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2020-08-15 17:03:213489semak imbas

示例php+mysql查询实现无限下级分类树输出

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.

【相关学习推荐:php编程(视频),mysql视频教程

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])
{
$str.="<span style=&#39;color:#CCCCCC&#39;>".$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(&#39;id&#39;=>1,&#39;name&#39;=>&#39;电脑&#39;,&#39;pid&#39;=>0),
  array(&#39;id&#39;=>2,&#39;name&#39;=>&#39;手机&#39;,&#39;pid&#39;=>0),
  array(&#39;id&#39;=>3,&#39;name&#39;=>&#39;笔记本&#39;,&#39;pid&#39;=>1),
  array(&#39;id&#39;=>4,&#39;name&#39;=>&#39;台式机&#39;,&#39;pid&#39;=>1),
  array(&#39;id&#39;=>5,&#39;name&#39;=>&#39;智能机&#39;,&#39;pid&#39;=>2),
  array(&#39;id&#39;=>6,&#39;name&#39;=>&#39;功能机&#39;,&#39;pid&#39;=>2),
  array(&#39;id&#39;=>7,&#39;name&#39;=>&#39;超级本&#39;,&#39;pid&#39;=>3),
  array(&#39;id&#39;=>8,&#39;name&#39;=>&#39;游戏本&#39;,&#39;pid&#39;=>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(
    &#39;id&#39;=>1,
    &#39;name&#39;=>&#39;电脑&#39;,
    &#39;pid&#39;=>0,
    children=>array(
      &array(
        &#39;id&#39;=>3,
        &#39;name&#39;=>&#39;笔记本&#39;,
        &#39;pid&#39;=>1,
        &#39;children&#39;=>array(
          //此处省略
        )
      ),
      &array(
        &#39;id&#39;=>4,
        &#39;name&#39;=>&#39;台式机&#39;,
        &#39;pid&#39;=>1,
        &#39;children&#39;=>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[&#39;id&#39;]] = $category;
  $tree[$category[&#39;id&#39;]][&#39;children&#39;] = 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[&#39;pid&#39;] != 0) {
    $tree[$item[&#39;pid&#39;]][&#39;children&#39;][] = &$tree[$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.

相关推荐:编程视频课程

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