不遗留问题-menu数据拼装

 DROP TABLE IF EXISTS `menu0910`;
 CREATE TABLE `menu0910` (
   `id` bigint(20) NOT NULL AUTO_INCREMENT,
   `menu` varchar(50) COLLATE utf8_unicode_ci DEFAULT '',
   `parentid` bigint(20) DEFAULT '',
   PRIMARY KEY (`id`)
 ) ENGINE=InnoDB AUTO_INCREMENT=40 DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;

 -- ----------------------------
 -- Records of menu0910
 -- ----------------------------
 INSERT INTO `menu0910` VALUES ('', '1-1', '');
 INSERT INTO `menu0910` VALUES ('', '1-2', '');
 INSERT INTO `menu0910` VALUES ('', '1-3', '');
 INSERT INTO `menu0910` VALUES ('', '1-1-1', '');
 INSERT INTO `menu0910` VALUES ('', '1-1-2', '');
 INSERT INTO `menu0910` VALUES ('', '1-1-3', '');
 INSERT INTO `menu0910` VALUES ('', '1-2-1', '');
 INSERT INTO `menu0910` VALUES ('', '1-2-2', '');
 INSERT INTO `menu0910` VALUES ('', '1-2-3', '');
 INSERT INTO `menu0910` VALUES ('', '1-3-1', '');
 INSERT INTO `menu0910` VALUES ('', '1-3-2', '');
 INSERT INTO `menu0910` VALUES ('', '1-3-3', '');
 INSERT INTO `menu0910` VALUES ('', '1-1-1-1', '');
 INSERT INTO `menu0910` VALUES ('', '1-1-1-2', '');
 INSERT INTO `menu0910` VALUES ('', '1-1-1-3', '');
 INSERT INTO `menu0910` VALUES ('', '1-1-2-1', '');
 INSERT INTO `menu0910` VALUES ('', '1-1-2-2', '');
 INSERT INTO `menu0910` VALUES ('', '1-1-2-3', '');
 INSERT INTO `menu0910` VALUES ('', '1-1-3-1', '');
 INSERT INTO `menu0910` VALUES ('', '1-1-3-2', '');
 INSERT INTO `menu0910` VALUES ('', '1-1-3-3', '');
 INSERT INTO `menu0910` VALUES ('', '1-2-1-1', '');
 INSERT INTO `menu0910` VALUES ('', '1-2-1-2', '');
 INSERT INTO `menu0910` VALUES ('', '1-2-1-3', '');
 INSERT INTO `menu0910` VALUES ('', '1-2-2-1', '');
 INSERT INTO `menu0910` VALUES ('', '1-2-2-2', '');
 INSERT INTO `menu0910` VALUES ('', '1-2-2-3', '');
 INSERT INTO `menu0910` VALUES ('', '1-2-3-1', '');
 INSERT INTO `menu0910` VALUES ('', '1-2-3-2', '');
 INSERT INTO `menu0910` VALUES ('', '1-2-3-3', '');
 INSERT INTO `menu0910` VALUES ('', '1-3-1-1', '');
 INSERT INTO `menu0910` VALUES ('', '1-3-1-2', '');
 INSERT INTO `menu0910` VALUES ('', '1-3-1-3', '');
 INSERT INTO `menu0910` VALUES ('', '1-3-2-1', '');
 INSERT INTO `menu0910` VALUES ('', '1-3-2-2', '');
 INSERT INTO `menu0910` VALUES ('', '1-3-2-3', '');
 INSERT INTO `menu0910` VALUES ('', '1-3-3-1', '');
 INSERT INTO `menu0910` VALUES ('', '1-3-3-2', '');
 INSERT INTO `menu0910` VALUES ('', '1-3-3-3', '');

<?php
$mysqli = new mysqli('localhost', 'root', '', 'w');

if ($mysqli->connect_errno) {
    printf("Connect failed: %s\n", $mysqli->connect_error);
    exit();
}

$menulist = array();
/* Select queries return a resultset */
if ($result = $mysqli->query("SELECT * FROM menu0910")) {
    printf("Select returned %d rows.\n", $result->num_rows);

    /* free result set */

    while ($row = $result->fetch_assoc()) {
        $menulist[] = $row;
    }

    $result->close();
}

var_dump($menulist);

//筛选出3级idlist->2级->1级
$idlist_3 = array();
$idlist_2 = array();
$idlist_1 = array();
$idlist_1_2_3 = array();
$idlist_1_2 = array();
foreach($menulist as $menu)
{
    $idlist_1_2_3[] = $menu['id'];
}
var_dump($idlist_1_2_3);
foreach($menulist as $menu)
{
    if($menu['parentid']!=0)$idlist_1_2[] = $menu['parentid'];
}
$idlist_1_2=array_unique($idlist_1_2);
var_dump($idlist_1_2);
foreach($idlist_1_2_3 as $id)
{
    if(!in_array($id,$idlist_1_2)) $idlist_3[] = $id;
}
var_dump($idlist_3);
foreach($idlist_3 as $id)
{
    $idlist_2[] = get_parentid($id);
}
$idlist_2=array_unique($idlist_2);
var_dump($idlist_2);

foreach($idlist_2 as $id)
{
    $idlist_1[] = get_parentid($id);
}
$idlist_1=array_unique($idlist_1);
var_dump($idlist_1);

function get_parentid($id)
{
    global $menulist;
    foreach($menulist as $one)
    {
        if($one['id']==$id) RETURN $one['parentid'];
    }
}

$res = array();
foreach($idlist_1 as $one)
{
    $res[] = $one;
}
var_dump($res);

$w = 0;
foreach($res as $id1)
{
    $tmp = array();
    foreach($idlist_2 as $id2)
    {
       if(get_parentid($id2) == $id1)$tmp[]=$id2;
    }
    $res[]=$tmp;
}
var_dump($res);