PHP uses recursive method to achieve unlimited classification and generate drop-down list

phpCustom functionRecursionImplementationInfinite classificationGenerate drop-down list, this can improve efficiency, and you don’t have to start from The database reads data.

The code is as follows:

/*—————————————————— */ 
//– 递归实现无限分类生成下拉列表函数 
//– $tpl->assign('sort_list',createSortOptions ()); 
//– $tpl->assign('sort_list',createSortOptions ($sort_id)); 
/*—————————————————— */ 
function createSortOptions ($selected=0,$parent_id=0,$n=-1) 
{ 
global $db; 
$sql = "SELECT * FROM `@article_sort` WHERE `parent_id` = '{$parent_id}'"; 
$options = "; 
static $i = 0; 
if ($i == 0) 
{ 
$options .= &#39;<option value="0″ >请选择</option>&#39;; 
} 
$res = $db->query ($sql); 
if ($res) 
{ 
$n++; 
while ($row = $db->fetch_assoc ($res)) 
{ 
$i++; 
$options .="<option value=&#39;{$row[&#39;sort_id&#39;]}&#39;"; 
if ($row[&#39;sort_id&#39;] == $selected) 
{ 
$options .=&#39; selected &#39;; 
} 
$options .=">".str_repeat(&#39; &#39;,$n*3).$row[&#39;sort_name&#39;]."</option>\n"; 
$options .=createSortOptions ($selected,$row[&#39;sort_id&#39;],$n); 
} 
} 
return $options; 
}

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