一个php递归函数.(code using PHP and MySql)

In Recurive funaction..(code using PHP and MySql)
When using a recursive function try not to use any iterative loops.
It increases the number of iterations at execution time.
In this example I am trying make a URL using a database and find the actual URL.
Both results are the same but the number of iterations is three times in the 2nd
option.
This is was practically happens :

<? 
//correct One 
function get_scat_url($temp_catid) { 
    static $url; 
    global $site_id=5; 
    if ($temp_catid != 0) { 
        $temp_sql=db_query("select sm_cat_id, sm_cat_pcat_id,      sm_cat_url, sm_cat_parentid from sitemap_category  where sm_cat_id ='". $temp_catid . "' and sm_domain_id ='". $site_id . "'"); 
        if (db_num_rows($temp_sql) > 0) { 
             $rec_set = db_fetch_array($temp_sql); 
             $url = $rec_set['sm_cat_url']. " : " . $url; 
             $temp_catid = $rec_set['sm_cat_parentid']; 
             get_scat_url($temp_catid); 
        } 
    }    //first if statement 
    return $url; 
} 
?> 
<? 
//incorrect recursive call in php program 
function get_scat_url($temp_catid){ 
    //global $url; 
    $site_id=5; 
    while($temp_catid != 0)  { 
        $temp_sql=db_query("select sm_cat_id, sm_cat_pcat_id, sm_cat_url, sm_cat_parentid from sitemap_category  where sm_cat_id ='". $temp_catid . "' and sm_domain_id ='". $site_id . "'"); 
        if (db_num_rows($temp_sql) > 0){ 
            $rec_set = db_fetch_array($temp_sql); 
            $url = $rec_set['sm_cat_url']. " : " . $url; 
            $temp_catid = $rec_set['sm_cat_parentid']; 
            get_scat_url($temp_catid); 
        } 
    }    //while ends here... 
    return $url; 
} 
?>