本文實例講述了php+mysql查詢實現無限下級分類樹輸出。分享給大家供大家參考，具體如下：
這里介紹的php結合mysql查詢無限下級樹輸出，其實就是無限分類。給各位整理了幾個php無限分類的例子.
樹輸出:
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']); //調用函數，傳入參數，繼續查詢下級 $arr[0]['children'][$key]['name']= $value['username']; //組合數組 if(is_array($r)){ $arr[0]['children'][$key]['children']= $r[0]['children']; } $i++; } return $arr; }$list = get_array("1000",1); //調用函數1000是頂級IDecho 'var data='.json_encode($list);這個是輸出 Array 然后轉讓為 json
例子:
表結構:id字段為分類標識，name字段為分類名,father_id字段為所屬父分類的id,path字段為分類路徑,儲存該分類祖先的集合,isdir判斷是否是目錄,1為是,0為否.
顯示函數:
//$count為分類等級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對象為sql操作類對象,re_datas()函數返回查到的數組,sql_numrows()函數返回查詢到的數目.
調用方法:
$sort_list = sort_list($sort_list,0,1);
例子:
表:category
id int 主鍵,自增
name varchar 分類名稱
pid int 父類id，默認0
頂級分類的 pid 默認就是0了,當我們想取出某個分類的子分類樹的時候,基本思路就是遞歸,當然,出于效率問題不建議每次遞歸都查詢數據庫,通常的做法是先講所有分類取出來,保存到PHP數組里,再進行處理,最后還可以將結果緩存起來以提高下次請求的效率.
先來構建一個原始數組,這個直接從數據庫中拉出來就行:
$categories = array( array('id'=>1,'name'=>'電腦','pid'=>0), array('id'=>2,'name'=>'手機','pid'=>0), array('id'=>3,'name'=>'筆記本','pid'=>1), array('id'=>4,'name'=>'臺式機','pid'=>1), array('id'=>5,'name'=>'智能機','pid'=>2), array('id'=>6,'name'=>'功能機','pid'=>2), array('id'=>7,'name'=>'超級本','pid'=>3), array('id'=>8,'name'=>'游戲本','pid'=>3),);目標是將它轉化為下面這種結構:
電腦—筆記本——-超級本——-游戲本—臺式機手機—智能機—功能機
用數組來表示的話,可以增加一個 children 鍵來存儲它的子分類:
array( //1對應id，方便直接讀取 1 => array( 'id'=>1, 'name'=>'電腦', 'pid'=>0, children=>array( &array( 'id'=>3, 'name'=>'筆記本', 'pid'=>1, 'children'=>array( //此處省略 ) ), &array( 'id'=>4, 'name'=>'臺式機', 'pid'=>1, 'children'=>array( //此處省略 ) ), ) ), //其他分類省略)
處理過程:
$tree = array();//第一步，將分類id作為數組key,并創建children單元foreach($categories as $category){ $tree[$category['id']] = $category; $tree[$category['id']]['children'] = array();}//第二部，利用引用，將每個分類添加到父類children數組中，這樣一次遍歷即可形成樹形結構。foreach ($tree as $k=>$item) { if ($item['pid'] != 0) { $tree[$item['pid']]['children'][] = &$tree[$k]; }}print_r($tree);打印結果如下:
Array( [1] => Array ( [id] => 1 [name] => 電腦 [pid] => 0 [children] => Array ( [0] => Array ( [id] => 3 [name] => 筆記本 [pid] => 1 [children] => Array ( [0] => Array ( [id] => 7 [name] => 超級本 [pid] => 3 [children] => Array ( ) ) [1] => Array ( [id] => 8 [name] => 游戲本 [pid] => 3 [children] => Array ( ) ) ) ) [1] => Array ( [id] => 4 [name] => 臺式機 [pid] => 1 [children] => Array ( ) ) ) ) [2] => Array ( [id] => 2 [name] => 手機 [pid] => 0 [children] => Array ( [0] => Array ( [id] => 5 [name] => 智能機 [pid] => 2 [children] => Array ( ) ) [1] => Array ( [id] => 6 [name] => 功能機 [pid] => 2 [children] => Array ( ) ) ) ) [3] => Array ( [id] => 3 [name] => 筆記本 [pid] => 1 [children] => Array ( [0] => Array ( [id] => 7 [name] => 超級本 [pid] => 3 [children] => Array ( ) ) [1] => Array ( [id] => 8 [name] => 游戲本 [pid] => 3 [children] => Array ( ) ) ) ) [4] => Array ( [id] => 4 [name] => 臺式機 [pid] => 1 [children] => Array ( ) ) [5] => Array ( [id] => 5 [name] => 智能機 [pid] => 2 [children] => Array ( ) ) [6] => Array ( [id] => 6 [name] => 功能機 [pid] => 2 [children] => Array ( ) ) [7] => Array ( [id] => 7 [name] => 超級本 [pid] => 3 [children] => Array ( ) ) [8] => Array ( [id] => 8 [name] => 游戲本 [pid] => 3 [children] => Array ( ) ))
優點:關系清楚,修改上下級關系簡單.
缺點:使用PHP處理,如果分類數量龐大,效率也會降低.
希望本文所述對大家PHP程序設計有所幫助。
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